diff --git a/assets/vue/components/coursemaintenance/ResourceSelector.vue b/assets/vue/components/coursemaintenance/ResourceSelector.vue
index b1e293697e0..b3d5b379cd7 100644
--- a/assets/vue/components/coursemaintenance/ResourceSelector.vue
+++ b/assets/vue/components/coursemaintenance/ResourceSelector.vue
@@ -85,7 +85,7 @@
 </template>
 
 <script setup>
-import { watch, toRefs, nextTick } from "vue"
+import { watch, toRefs } from "vue"
 import useResourceSelection from "../../composables/coursemaintenance/useResourceSelection"
 
 const props = defineProps({
@@ -103,7 +103,7 @@ const props = defineProps({
 
 const emit = defineEmits(["update:modelValue"])
 
-// hook with shared logic
+// Shared selection logic (composable)
 const sel = useResourceSelection()
 const {
   tree,
@@ -121,13 +121,115 @@ const {
   expandAll,
 } = sel
 
-// sync in/out
+/**
+ * Transform the "Documents" group into a real folder/file tree using relative paths.
+ * - Real folders (filetype === 'folder' or path ends with '/') remain as selectable only if they were.
+ * - Synthetic folders (created by this function) are NOT selectable and use string ids (__dir__<rel>).
+ * - Adds node.meta with the relative path to improve search filtering.
+ * - Keeps everything else unchanged for other groups.
+ */
+function treeifyDocuments(groups) {
+  const out = Array.isArray(groups) ? groups : []
+  for (const g of out) {
+    if (!g || g.type !== "document") continue
+
+    const flat = Array.isArray(g.children) ? g.children : Array.isArray(g.items) ? g.items : []
+    if (!flat.length) continue
+
+    // Compute relative path (strip "document/" prefix if present)
+    const relOf = (n) => {
+      const raw = String(n?.extra?.path || n?.label || "").trim()
+      if (!raw) return null
+      let rel = raw.replace(/^\/?document\/?/, "").replace(/\\/g, "/")
+      const isFolder = String(n?.extra?.filetype || "").toLowerCase() === "folder" || /\/$/.test(rel)
+      if (isFolder) rel = rel.replace(/\/+$/, "") + "/"
+      return rel.replace(/^\/+/, "")
+    }
+
+    // Index existing (real) folders
+    const folderMap = new Map() // rel => node
+    for (const it of flat) {
+      const rel = relOf(it)
+      if (!rel) continue
+      const isFolder = String(it?.extra?.filetype || "").toLowerCase() === "folder" || rel.endsWith("/")
+      if (isFolder) {
+        it.label = (rel.replace(/\/$/, "").split("/").pop() || "/") + "/"
+        it.meta = rel
+        it.children = Array.isArray(it.children) ? it.children : []
+        folderMap.set(rel, it)
+      }
+    }
+
+    // Create synthetic folder if missing for a given relative path
+    const ensureFolder = (rel) => {
+      if (folderMap.has(rel)) return folderMap.get(rel)
+      const name = rel.replace(/\/$/, "").split("/").pop() || "/"
+      const synthetic = {
+        id: `__dir__${rel}`,
+        type: "document",
+        label: name + "/",
+        meta: rel,
+        selectable: false, // synthetic folders shouldn't be checkable
+        children: [],
+        extra: { filetype: "folder" },
+      }
+      folderMap.set(rel, synthetic)
+      return synthetic
+    }
+
+    const parentRelOf = (rel, isFolder) => {
+      const clean = isFolder ? rel.replace(/\/+$/, "") : rel
+      const dir = clean.includes("/") ? clean.slice(0, clean.lastIndexOf("/")) : ""
+      return dir ? dir + "/" : ""
+    }
+
+    const root = { children: [] }
+
+    // Place each item under its parent folder chain
+    for (const it of flat) {
+      const rel = relOf(it)
+      if (!rel) continue
+      const isFolder = String(it?.extra?.filetype || "").toLowerCase() === "folder" || rel.endsWith("/")
+      const parentRel = parentRelOf(rel, isFolder)
+      const parent = parentRel ? ensureFolder(parentRel) : root
+
+      if (isFolder) {
+        const f = ensureFolder(rel)
+        if (!parent.children.includes(f)) parent.children.push(f)
+      } else {
+        const n = { ...it, meta: rel, label: rel.split("/").pop() }
+        parent.children.push(n)
+      }
+    }
+
+    // Sort: folders first, then files (case-insensitive)
+    const sortChildren = (list) => {
+      list.sort((a, b) => {
+        const af = (a.extra?.filetype || "").toLowerCase() === "folder" || /\/$/.test(a.label || "")
+        const bf = (b.extra?.filetype || "").toLowerCase() === "folder" || /\/$/.test(b.label || "")
+        if (af !== bf) return af ? -1 : 1
+        return String(a.label || "").localeCompare(String(b.label || ""), undefined, { sensitivity: "base" })
+      })
+      for (const n of list) if (n.children?.length) sortChildren(n.children)
+    }
+    sortChildren(root.children)
+
+    g.children = root.children
+    delete g.items
+  }
+  return out
+}
+
+// sync input => internal tree
 const { groups, modelValue } = toRefs(props)
 watch(
   groups,
   (arr) => {
-    const norm = normalizeTreeForSelection(Array.isArray(arr) ? JSON.parse(JSON.stringify(arr)) : [])
-    // ensure top-level children
+    // Normalize the incoming tree first (ensures leaves have id/type/selectable)
+    let norm = normalizeTreeForSelection(Array.isArray(arr) ? JSON.parse(JSON.stringify(arr)) : [])
+    // Build the folder/file hierarchy only for Documents
+    norm = treeifyDocuments(norm)
+    // Ensure top-level children exist
     tree.value = norm.map((g) =>
       Array.isArray(g.children) ? g : { ...g, children: Array.isArray(g.items) ? g.items : [] },
     )
@@ -135,7 +237,7 @@ watch(
   { immediate: true },
 )
 
-// auto expand on first data
+// auto expand on first data load
 watch(tree, (v) => {
   if (Array.isArray(v) && v.length) {
     forceOpen.value = true
@@ -147,6 +249,7 @@ watch(tree, (v) => {
 
 let syncing = false
 
+// v-model (in) -> local
 watch(
   modelValue,
   (v) => {
@@ -160,6 +263,7 @@ watch(
   { immediate: true },
 )
 
+// local -> v-model (out)
 watch(
   selections,
   (v) => {
@@ -175,7 +279,7 @@ watch(
 </script>
 
 <script>
-/* inline child components to keep it self-contained */
+/* Inline child components to keep it self-contained */
 export default {
   components: {
     GroupBlock: {
@@ -190,7 +294,7 @@ export default {
       },
       emits: ["select-group"],
       components: {
-        /* <-- REGISTER TreeNode LOCALLY HERE */
+        /* <-- Tree node item (no type badge; uses folder/file icon) */
         TreeNode: {
           name: "TreeNode",
           props: {
@@ -220,14 +324,12 @@ export default {
             onCheck(e) {
               this.$emit("toggle", e.target.checked)
             },
-            badgeTone() {
-              return "bg-gray-10 text-gray-90 ring-gray-25"
-            },
           },
           template: `
             <li class="p-3 rounded-lg hover:bg-gray-15 transition">
               <div class="flex items-start gap-3">
 
+                <!-- Disclosure -->
                 <div class="mt-0.5 w-5 flex items-center justify-center">
                   <button
                     class="text-gray-50 hover:text-gray-90"
@@ -238,6 +340,7 @@ export default {
                   </button>
                 </div>
 
+                <!-- Checkbox only for checkable nodes -->
                 <template v-if="isNodeCheckable(node)">
                   <input type="checkbox" :checked="checked" @change="onCheck" class="mt-0.5 chk-success"/>
                 </template>
@@ -245,13 +348,15 @@ export default {
                   <span class="mt-0.5 w-5"></span>
                 </template>
 
+                <!-- Label with folder/file icon (no type badge) -->
                 <div class="flex-1">
                   <div class="flex items-center gap-2">
-        <span class="rounded px-2 py-0.5 text-xs font-semibold ring-1 ring-inset" :class="badgeTone()">
-          {{ (node.titleType || node.type || '').toUpperCase() }}
-        </span>
-                    <span class="text-sm text-gray-90">{{ node.label || node.title || '—' }}</span>
-                    <span v-if="node.meta" class="text-xs text-gray-50">· {{ node.meta }}</span>
+                    <i
+                      :class="((node.extra && node.extra.filetype === 'folder') || /\\/$/.test(node.label || ''))
+                        ? 'mdi mdi-folder'
+                        : 'mdi mdi-file-outline'"></i>
+                    <span class="text-sm text-gray-90 break-all">{{ node.label || node.title || '—' }}</span>
+                    <span v-if="node.meta" class="text-xs text-gray-50 break-all">· {{ node.meta }}</span>
                   </div>
 
                   <ul v-if="open && node.children && node.children.length" class="mt-2 ml-7 space-y-2">
diff --git a/src/CoreBundle/Controller/CourseMaintenanceController.php b/src/CoreBundle/Controller/CourseMaintenanceController.php
index 6894bb8d029..fb621161688 100644
--- a/src/CoreBundle/Controller/CourseMaintenanceController.php
+++ b/src/CoreBundle/Controller/CourseMaintenanceController.php
@@ -29,7 +29,6 @@
 use Throwable;
 
 use const ARRAY_FILTER_USE_BOTH;
-use const DIRECTORY_SEPARATOR;
 use const JSON_UNESCAPED_SLASHES;
 use const JSON_UNESCAPED_UNICODE;
 use const PATHINFO_EXTENSION;
@@ -137,42 +136,29 @@ public function importServerPick(int $node, Request $req): JsonResponse
     public function importResources(int $node, string $backupId, Request $req): JsonResponse
     {
         $this->setDebugFromRequest($req);
-        $this->logDebug('[importResources] begin', ['node' => $node, 'backupId' => $backupId]);
+        $mode = strtolower((string) $req->query->get('mode', 'auto')); // 'auto' | 'dat' | 'moodle'
 
-        try {
-            $course = $this->loadLegacyCourseForAnyBackup($backupId);
-
-            $this->logDebug('[importResources] course loaded', [
-                'has_resources' => \is_array($course->resources ?? null),
-                'keys' => array_keys((array) ($course->resources ?? [])),
-            ]);
-            $this->logDebug('[importResources] resources snapshot', $this->snapshotResources($course));
-            $this->logDebug('[importResources] forum counts', $this->snapshotForumCounts($course));
-
-            $tree = $this->buildResourceTreeForVue($course);
-            $this->logDebug(
-                '[importResources] UI tree groups',
-                array_map(fn ($g) => ['type' => $g['type'], 'title' => $g['title'], 'items' => \count($g['items'] ?? [])], $tree)
-            );
+        // Reutilizas TU loader actual con el nuevo flag
+        $course = $this->loadLegacyCourseForAnyBackup($backupId, $mode === 'dat' ? 'chamilo' : $mode);
 
-            $warnings = [];
-            if (empty($tree)) {
-                $warnings[] = 'Backup has no selectable resources.';
-            }
+        // Lo demás igual
+        $this->logDebug('[importResources] course loaded', [
+            'has_resources' => \is_array($course->resources ?? null),
+            'keys' => array_keys((array) ($course->resources ?? [])),
+        ]);
 
-            return $this->json([
-                'tree' => $tree,
-                'warnings' => $warnings,
-            ]);
-        } catch (Throwable $e) {
-            $this->logDebug('[importResources] exception', ['message' => $e->getMessage()]);
+        $tree = $this->buildResourceTreeForVue($course);
 
-            return $this->json([
-                'ok' => false,
-                'tree' => [],
-                'warnings' => ['Error reading backup: '.$e->getMessage()],
-            ], 500);
+        $warnings = [];
+        if (empty($tree)) {
+            $warnings[] = 'Backup has no selectable resources.';
         }
+
+        return $this->json([
+            'tree'     => $tree,
+            'warnings' => $warnings,
+            'meta'     => ['import_source' => $course->resources['__meta']['import_source'] ?? null],
+        ]);
     }
 
     #[Route(
@@ -671,11 +657,26 @@ public function moodleExportOptions(int $node, Request $req, UserRepository $use
             'admin' => $users->getDefaultAdminForExport(),
         ];
 
+        $tools = [
+            ['value' => 'documents', 'label' => 'Documents (files & root HTML pages)'],
+            ['value' => 'links', 'label' => 'Links (URL)'],
+            ['value' => 'forums', 'label' => 'Forums'],
+            ['value' => 'quizzes', 'label' => 'Quizzes', 'implies' => ['quiz_questions']],
+            ['value' => 'surveys', 'label' => 'Surveys', 'implies' => ['survey_questions']],
+            ['value' => 'works', 'label' => 'Tasks'],
+            ['value' => 'glossary', 'label' => 'Glossary'],
+            ['value' => 'learnpaths', 'label' => 'Paths learning'],
+            ['value' => 'tool_intro', 'label' => 'Course Introduction'],
+        ];
+
+        $defaults['tools'] = array_column($tools, 'value');
+
         return $this->json([
             'versions' => [
                 ['value' => '3', 'label' => 'Moodle 3.x'],
                 ['value' => '4', 'label' => 'Moodle 4.x'],
             ],
+            'tools' => $tools,
             'defaults' => $defaults,
         ]);
     }
@@ -683,35 +684,95 @@ public function moodleExportOptions(int $node, Request $req, UserRepository $use
     #[Route('/moodle/export/resources', name: 'moodle_export_resources', methods: ['GET'])]
     public function moodleExportResources(int $node, Request $req): JsonResponse
     {
+        // Enable/disable debug from request
         $this->setDebugFromRequest($req);
+        $this->logDebug('[moodleExportResources] start', ['node' => $node]);
 
-        // Build legacy Course from CURRENT course (same approach as recycle)
-        $cb = new CourseBuilder();
-        $cb->set_tools_to_build([
-            'documents', 'forums', 'tool_intro', 'links', 'quizzes', 'quiz_questions', 'assets', 'surveys',
-            'survey_questions', 'announcements', 'events', 'course_descriptions', 'glossary', 'wiki',
-            'thematic', 'attendance', 'works', 'gradebook', 'learnpath_category', 'learnpaths',
-        ]);
-        $course = $cb->build(0, api_get_course_id());
+        try {
+            // Normalize incoming tools from query (?tools[]=documents&tools[]=links ...)
+            $selectedTools = $this->normalizeSelectedTools($req->query->all('tools'));
+
+            // Default toolset tailored for Moodle export picker:
+            $defaultToolsForMoodle = [
+                'documents', 'links', 'forums',
+                'quizzes', 'quiz_questions',
+                'surveys', 'survey_questions',
+                'learnpaths', 'learnpath_category',
+                'works', 'glossary',
+                'tool_intro',
+            ];
 
-        $tree = $this->buildResourceTreeForVue($course);
-        $warnings = empty($tree) ? ['This course has no resources.'] : [];
+            // Use client tools if provided; otherwise our Moodle-safe defaults
+            $tools = !empty($selectedTools) ? $selectedTools : $defaultToolsForMoodle;
 
-        return $this->json(['tree' => $tree, 'warnings' => $warnings]);
+            // Policy for this endpoint:
+            //  - Never show gradebook
+            //  - Always include tool_intro in the picker (harmless if empty)
+            $tools = array_values(array_diff($tools, ['gradebook']));
+            if (!in_array('tool_intro', $tools, true)) {
+                $tools[] = 'tool_intro';
+            }
+
+            $this->logDebug('[moodleExportResources] tools to build', $tools);
+
+            // Build legacy Course snapshot from CURRENT course (not from a source course)
+            $cb = new CourseBuilder();
+            $cb->set_tools_to_build($tools);
+            $course = $cb->build(0, api_get_course_id());
+
+            // Build the UI-friendly tree
+            $tree = $this->buildResourceTreeForVue($course);
+
+            // Basic warnings for the client
+            $warnings = empty($tree) ? ['This course has no resources.'] : [];
+
+            // Some compact debug about the resulting tree
+            if ($this->debug) {
+                $this->logDebug(
+                    '[moodleExportResources] tree summary',
+                    array_map(
+                        fn ($g) => [
+                            'type'     => $g['type'] ?? '',
+                            'title'    => $g['title'] ?? '',
+                            'items'    => isset($g['items']) ? \count((array) $g['items']) : null,
+                            'children' => isset($g['children']) ? \count((array) $g['children']) : null,
+                        ],
+                        $tree
+                    )
+                );
+            }
+
+            return $this->json([
+                'tree'     => $tree,
+                'warnings' => $warnings,
+            ]);
+        } catch (\Throwable $e) {
+            // Defensive error path
+            $this->logDebug('[moodleExportResources] exception', [
+                'message' => $e->getMessage(),
+                'file'    => $e->getFile().':'.$e->getLine(),
+            ]);
+
+            return $this->json([
+                'error'   => 'Failed to build resource tree for Moodle export.',
+                'details' => $e->getMessage(),
+            ], 500);
+        }
     }
 
     #[Route('/moodle/export/execute', name: 'moodle_export_execute', methods: ['POST'])]
-    public function moodleExportExecute(int $node, Request $req, UserRepository $users): BinaryFileResponse|JsonResponse
+    public function moodleExportExecute(int $node, Request $req, UserRepository $users): JsonResponse|BinaryFileResponse
     {
         $this->setDebugFromRequest($req);
 
         $p = json_decode($req->getContent() ?: '{}', true);
-        $moodleVersion = (string) ($p['moodleVersion'] ?? '4');   // '3' | '4'
-        $scope = (string) ($p['scope'] ?? 'full');        // 'full' | 'selected'
+        $moodleVersion = (string) ($p['moodleVersion'] ?? '4');
+        $scope = (string) ($p['scope'] ?? 'full');
         $adminId = (int) ($p['adminId'] ?? 0);
         $adminLogin = trim((string) ($p['adminLogin'] ?? ''));
         $adminEmail = trim((string) ($p['adminEmail'] ?? ''));
         $selected = (array) ($p['resources'] ?? []);
+        $toolsInput = (array) ($p['tools'] ?? []);
 
         if (!\in_array($moodleVersion, ['3', '4'], true)) {
             return $this->json(['error' => 'Unsupported Moodle version'], 400);
@@ -720,6 +781,20 @@ public function moodleExportExecute(int $node, Request $req, UserRepository $use
             return $this->json(['error' => 'No resources selected'], 400);
         }
 
+        // Normalize tools from client (adds implied deps)
+        $tools = $this->normalizeSelectedTools($toolsInput);
+
+        // If scope=selected, merge inferred tools from selection
+        if ('selected' === $scope) {
+            $inferred = $this->inferToolsFromSelection($selected);
+            $tools = $this->normalizeSelectedTools(array_merge($tools, $inferred));
+        }
+
+        $tools = array_values(array_unique(array_diff($tools, ['gradebook'])));
+        if (!in_array('tool_intro', $tools, true)) {
+            $tools[] = 'tool_intro';
+        }
+
         if ($adminId <= 0 || '' === $adminLogin || '' === $adminEmail) {
             $adm = $users->getDefaultAdminForExport();
             $adminId = $adminId > 0 ? $adminId : (int) ($adm['id'] ?? 1);
@@ -727,13 +802,18 @@ public function moodleExportExecute(int $node, Request $req, UserRepository $use
             $adminEmail = '' !== $adminEmail ? $adminEmail : (string) ($adm['email'] ?? 'admin@example.com');
         }
 
-        // Build legacy Course from CURRENT course (same approach as recycle)
+        $this->logDebug('[moodleExportExecute] tools for CourseBuilder', $tools);
+
+        // Build legacy Course from CURRENT course
         $cb = new CourseBuilder();
-        $cb->set_tools_to_build([
-            'documents', 'links', 'quizzes', 'quiz_questions', 'surveys', 'survey_questions',
-            'announcements', 'events', 'course_descriptions', 'glossary', 'wiki', 'thematic',
-            'attendance', 'works', 'gradebook', 'learnpath_category', 'learnpaths', 'tool_intro',
-            'forums',
+        $cb->set_tools_to_build(!empty($tools) ? $tools : [
+            // Fallback should mirror the Moodle-safe list used in the picker
+            'documents', 'links', 'forums',
+            'quizzes', 'quiz_questions',
+            'surveys', 'survey_questions',
+            'learnpaths', 'learnpath_category',
+            'works', 'glossary',
+            'tool_intro',
         ]);
         $course = $cb->build(0, api_get_course_id());
 
@@ -741,7 +821,6 @@ public function moodleExportExecute(int $node, Request $req, UserRepository $use
         if ('selected' === $scope) {
             // This method trims buckets to only selected items and pulls needed deps (LP/quiz/survey)
             $course = $this->filterLegacyCourseBySelection($course, $selected);
-
             // Safety guard: fail if nothing remains after filtering
             if (empty($course->resources) || !\is_array($course->resources)) {
                 return $this->json(['error' => 'Selection produced no resources to export'], 400);
@@ -772,6 +851,45 @@ public function moodleExportExecute(int $node, Request $req, UserRepository $use
         }
     }
 
+    /**
+     * Normalize tool list to supported ones and add implied dependencies.
+     *
+     * @param array<int,string>|null $tools
+     * @return string[]
+     */
+    private function normalizeSelectedTools(?array $tools): array
+    {
+        // Single list of supported tool buckets (must match CourseBuilder/exporters)
+        $all = [
+            'documents','links','quizzes','quiz_questions','surveys','survey_questions',
+            'announcements','events','course_descriptions','glossary','wiki','thematic',
+            'attendance','works','gradebook','learnpath_category','learnpaths','tool_intro','forums',
+        ];
+
+        // Implied dependencies
+        $deps = [
+            'quizzes'    => ['quiz_questions'],
+            'surveys'    => ['survey_questions'],
+            'learnpaths' => ['learnpath_category'],
+        ];
+
+        $sel = is_array($tools) ? array_values(array_intersect($tools, $all)) : [];
+
+        foreach ($sel as $t) {
+            foreach ($deps[$t] ?? [] as $d) {
+                $sel[] = $d;
+            }
+        }
+
+        // Unique and preserve a sane order based on $all
+        $sel = array_values(array_unique($sel));
+        usort($sel, static function ($a, $b) use ($all) {
+            return array_search($a, $all, true) <=> array_search($b, $all, true);
+        });
+
+        return $sel;
+    }
+
     #[Route('/cc13/export/options', name: 'cc13_export_options', methods: ['GET'])]
     public function cc13ExportOptions(int $node, Request $req): JsonResponse
     {
@@ -794,21 +912,17 @@ public function cc13ExportResources(int $node, Request $req): JsonResponse
         $course = $cb->build(0, api_get_course_id());
 
         $treeAll = $this->buildResourceTreeForVue($course);
-        $tree = Cc13Capabilities::filterTree($treeAll);
+        $tree    = Cc13Capabilities::filterTree($treeAll);
 
         // Count exportables using "items"
         $exportableCount = 0;
         foreach ($tree as $group) {
-            if (empty($group['items']) || !\is_array($group['items'])) {
-                continue;
-            }
+            if (empty($group['items']) || !\is_array($group['items'])) { continue; }
 
             if (($group['type'] ?? '') === 'forum') {
                 foreach ($group['items'] as $cat) {
                     foreach (($cat['items'] ?? []) as $forumNode) {
-                        if (($forumNode['type'] ?? '') === 'forum') {
-                            $exportableCount++;
-                        }
+                        if (($forumNode['type'] ?? '') === 'forum') { $exportableCount++; }
                     }
                 }
             } else {
@@ -817,37 +931,37 @@ public function cc13ExportResources(int $node, Request $req): JsonResponse
         }
 
         $warnings = [];
-        if (0 === $exportableCount) {
+        if ($exportableCount === 0) {
             $warnings[] = 'This course has no CC 1.3 exportable resources (documents, links or forums).';
         }
 
         return $this->json([
             'supportedTypes' => Cc13Capabilities::exportableTypes(), // ['document','link','forum']
-            'tree' => $tree,
-            'preview' => ['counts' => ['total' => $exportableCount]],
-            'warnings' => $warnings,
+            'tree'           => $tree,
+            'preview'        => ['counts' => ['total' => $exportableCount]],
+            'warnings'       => $warnings,
         ]);
     }
 
     #[Route('/cc13/export/execute', name: 'cc13_export_execute', methods: ['POST'])]
     public function cc13ExportExecute(int $node, Request $req): JsonResponse
     {
-        $payload = json_decode((string) $req->getContent(), true) ?: [];
+        $payload  = json_decode((string) $req->getContent(), true) ?: [];
         // If the client sent "resources", treat as selected even if scope says "full".
-        $scope = (string) ($payload['scope'] ?? (!empty($payload['resources']) ? 'selected' : 'full'));
-        $selected = (array) ($payload['resources'] ?? []);
+        $scope    = (string) ($payload['scope'] ?? (!empty($payload['resources']) ? 'selected' : 'full'));
+        $selected = (array)  ($payload['resources'] ?? []);
 
         // Normalize selection structure (documents/links/forums/…)
         $normSel = Cc13Capabilities::filterSelection($selected);
 
         // Builder setup
         $tools = ['documents', 'links', 'forums'];
-        $cb = new CourseBuilder();
+        $cb    = new CourseBuilder();
 
         $selectionMode = false;
 
         try {
-            if ('selected' === $scope) {
+            if ($scope === 'selected') {
                 // Build a full snapshot first to expand any category-only selections.
                 $cbFull = new CourseBuilder();
                 $cbFull->set_tools_to_build($tools);
@@ -857,15 +971,9 @@ public function cc13ExportExecute(int $node, Request $req): JsonResponse
 
                 // Build per-tool ID map for CourseBuilder
                 $map = [];
-                if (!empty($expanded['documents'])) {
-                    $map['documents'] = array_map('intval', array_keys($expanded['documents']));
-                }
-                if (!empty($expanded['links'])) {
-                    $map['links'] = array_map('intval', array_keys($expanded['links']));
-                }
-                if (!empty($expanded['forums'])) {
-                    $map['forums'] = array_map('intval', array_keys($expanded['forums']));
-                }
+                if (!empty($expanded['documents'])) { $map['documents'] = array_map('intval', array_keys($expanded['documents'])); }
+                if (!empty($expanded['links']))     { $map['links']     = array_map('intval', array_keys($expanded['links'])); }
+                if (!empty($expanded['forums']))    { $map['forums']    = array_map('intval', array_keys($expanded['forums'])); }
 
                 if (empty($map)) {
                     return $this->json(['error' => 'Please select at least one resource.'], 400);
@@ -885,15 +993,15 @@ public function cc13ExportExecute(int $node, Request $req): JsonResponse
                 // Convert to the expected structure for filterCourseResources()
                 $safeSelected = [
                     'documents' => array_fill_keys(array_map('intval', array_keys($normSel['documents'] ?? [])), true),
-                    'links' => array_fill_keys(array_map('intval', array_keys($normSel['links'] ?? [])), true),
-                    'forums' => array_fill_keys(array_map('intval', array_keys($normSel['forums'] ?? [])), true),
+                    'links'     => array_fill_keys(array_map('intval', array_keys($normSel['links'] ?? [])), true),
+                    'forums'    => array_fill_keys(array_map('intval', array_keys($normSel['forums'] ?? [])), true),
                 ];
                 // Also include expansions from categories
                 $fullSnapshot = isset($courseFull) ? $courseFull : $course;
-                $expandedAll = $this->expandCc13SelectionFromCategories($fullSnapshot, $normSel);
-                foreach (['documents', 'links', 'forums'] as $k) {
+                $expandedAll  = $this->expandCc13SelectionFromCategories($fullSnapshot, $normSel);
+                foreach (['documents','links','forums'] as $k) {
                     foreach (array_keys($expandedAll[$k] ?? []) as $idStr) {
-                        $safeSelected[$k][(int) $idStr] = true;
+                        $safeSelected[$k][(int)$idStr] = true;
                     }
                 }
 
@@ -903,27 +1011,26 @@ public function cc13ExportExecute(int $node, Request $req): JsonResponse
                 }
             }
 
-            $exporter = new Cc13Export($course, $selectionMode, /* debug */ false);
+            $exporter  = new Cc13Export($course, $selectionMode, /*debug*/ false);
             $imsccPath = $exporter->export(api_get_course_id());
-            $fileName = basename($imsccPath);
+            $fileName  = basename($imsccPath);
 
             $downloadUrl = $this->generateUrl(
-                'cm_cc13_export_download',
-                ['node' => $node],
-                UrlGeneratorInterface::ABSOLUTE_URL
-            ).'?file='.rawurlencode($fileName);
+                    'cm_cc13_export_download',
+                    ['node' => $node],
+                    UrlGeneratorInterface::ABSOLUTE_URL
+                ).'?file='.rawurlencode($fileName);
 
             return $this->json([
-                'ok' => true,
-                'file' => $fileName,
+                'ok'          => true,
+                'file'        => $fileName,
                 'downloadUrl' => $downloadUrl,
-                'message' => 'Export finished.',
+                'message'     => 'Export finished.',
             ]);
-        } catch (RuntimeException $e) {
-            if (false !== stripos($e->getMessage(), 'Nothing to export')) {
+        } catch (\RuntimeException $e) {
+            if (stripos($e->getMessage(), 'Nothing to export') !== false) {
                 return $this->json(['error' => 'Nothing to export (no compatible resources found).'], 400);
             }
-
             return $this->json(['error' => 'CC 1.3 export failed: '.$e->getMessage()], 500);
         }
     }
@@ -934,11 +1041,11 @@ public function cc13ExportDownload(int $node, Request $req): BinaryFileResponse|
         // Validate the filename we will serve
         $file = basename((string) $req->query->get('file', ''));
         // Example pattern: ABC123_cc13_20251017_195455.imscc
-        if ('' === $file || !preg_match('/^[A-Za-z0-9_-]+_cc13_\d{8}_\d{6}\.imscc$/', $file)) {
+        if ($file === '' || !preg_match('/^[A-Za-z0-9_-]+_cc13_\d{8}_\d{6}\.imscc$/', $file)) {
             return $this->json(['error' => 'Invalid file'], 400);
         }
 
-        $abs = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR.$file;
+        $abs = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR) . DIRECTORY_SEPARATOR . $file;
         if (!is_file($abs)) {
             return $this->json(['error' => 'File not found'], 404);
         }
@@ -964,21 +1071,21 @@ public function cc13Import(int $node, Request $req): JsonResponse
             }
 
             $ext = strtolower(pathinfo($file->getClientOriginalName() ?? '', PATHINFO_EXTENSION));
-            if (!\in_array($ext, ['imscc', 'zip'], true)) {
+            if (!in_array($ext, ['imscc', 'zip'], true)) {
                 return $this->json(['error' => 'Unsupported file type. Please upload .imscc or .zip'], 415);
             }
 
             // Move to a temp file
             $tmpZip = rtrim(sys_get_temp_dir(), DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR.
                 'cc13_'.date('Ymd_His').'_'.bin2hex(random_bytes(3)).'.'.$ext;
-            $file->move(\dirname($tmpZip), basename($tmpZip));
+            $file->move(dirname($tmpZip), basename($tmpZip));
 
             // Extract
             $extractDir = Imscc13Import::unzip($tmpZip);
 
             // Detect and validate format
             $format = Imscc13Import::detectFormat($extractDir);
-            if (Imscc13Import::FORMAT_IMSCC13 !== $format) {
+            if ($format !== Imscc13Import::FORMAT_IMSCC13) {
                 Imscc13Import::rrmdir($extractDir);
                 @unlink($tmpZip);
 
@@ -997,16 +1104,413 @@ public function cc13Import(int $node, Request $req): JsonResponse
                 'ok' => true,
                 'message' => 'CC 1.3 import completed successfully.',
             ]);
-        } catch (Throwable $e) {
+        } catch (\Throwable $e) {
             return $this->json([
                 'error' => 'CC 1.3 import failed: '.$e->getMessage(),
             ], 500);
         }
     }
 
-    // --------------------------------------------------------------------------------
-    // Helpers to build the Vue-ready resource tree
-    // --------------------------------------------------------------------------------
+    #[Route(
+        '/import/{backupId}/diagnose',
+        name: 'import_diagnose',
+        requirements: ['backupId' => '.+'],
+        methods: ['GET']
+    )]
+    public function importDiagnose(int $node, string $backupId, Request $req): JsonResponse
+    {
+        $this->setDebugFromRequest($req);
+        $this->logDebug('[importDiagnose] begin', ['node' => $node, 'backupId' => $backupId]);
+
+        try {
+            // Resolve absolute path of the uploaded/selected backup
+            $path = $this->resolveBackupPath($backupId);
+            if (!is_file($path)) {
+                return $this->json(['error' => 'Backup file not found', 'path' => $path], 404);
+            }
+
+            // Read course_info.dat bytes from ZIP
+            $ci = $this->readCourseInfoFromZip($path);
+            if (empty($ci['ok'])) {
+                $this->logDebug('[importDiagnose] course_info.dat not found or unreadable', $ci);
+
+                return $this->json([
+                    'meta' => [
+                        'backupId' => $backupId,
+                        'path'     => $path,
+                    ],
+                    'zip' => [
+                        'error'           => $ci['error'] ?? 'unknown error',
+                        'zip_list_sample' => $ci['zip_list_sample'] ?? [],
+                        'num_files'       => $ci['num_files'] ?? null,
+                    ],
+                ], 200);
+            }
+
+            $raw  = (string) $ci['data'];
+            $size = (int) ($ci['size'] ?? strlen($raw));
+            $md5  = md5($raw);
+
+            // Detect & decode content
+            $probe = $this->decodeCourseInfo($raw);
+
+            // Build a tiny scan snapshot (only keys, no grafo)
+            $scan = [
+                'has_graph'      => false,
+                'resources_keys' => [],
+                'note'           => 'No graph parsed',
+            ];
+
+            if (!empty($probe['is_serialized']) && isset($probe['value']) && \is_object($probe['value'])) {
+                /** @var object $course */
+                $course = $probe['value'];
+                $scan['has_graph'] = true;
+                $scan['resources_keys'] = (isset($course->resources) && \is_array($course->resources))
+                    ? array_keys($course->resources)
+                    : [];
+                $scan['note'] = 'Parsed PHP serialized graph';
+            } elseif (!empty($probe['is_json']) && \is_array($probe['json_preview'])) {
+                $jp = $probe['json_preview'];
+                $scan['has_graph'] = true;
+                $scan['resources_keys'] = (isset($jp['resources']) && \is_array($jp['resources']))
+                    ? array_keys($jp['resources'])
+                    : [];
+                $scan['note'] = 'Parsed JSON document';
+            }
+
+            $probeOut = $probe;
+            unset($probeOut['value'], $probeOut['decoded']);
+
+            $out = [
+                'meta' => [
+                    'backupId' => $backupId,
+                    'path'     => $path,
+                    'node'     => $node,
+                ],
+                'zip' => [
+                    'name'  => $ci['name'] ?? null,
+                    'index' => $ci['index'] ?? null,
+                ],
+                'course_info_dat' => [
+                    'size_bytes' => $size,
+                    'md5'        => $md5,
+                ],
+                'probe' => $probeOut,
+                'scan'  => $scan,
+            ];
+
+            $this->logDebug('[importDiagnose] done', [
+                'encoding'       => $probeOut['encoding'] ?? null,
+                'has_graph'      => $scan['has_graph'],
+                'resources_keys' => $scan['resources_keys'],
+            ]);
+
+            return $this->json($out);
+        } catch (\Throwable $e) {
+            $this->logDebug('[importDiagnose] exception', ['message' => $e->getMessage()]);
+
+            return $this->json([
+                'error' => 'Diagnosis failed: '.$e->getMessage(),
+            ], 500);
+        }
+    }
+
+    /**
+     * Try to detect and decode course_info.dat content.
+     * Hardened: preprocess typed-prop numeric strings and register legacy aliases
+     * before attempting unserialize. Falls back to relaxed mode to avoid typed
+     * property crashes during diagnosis.
+     */
+    private function decodeCourseInfo(string $raw): array
+    {
+        $r = [
+            'encoding'      => 'raw',
+            'decoded_len'   => strlen($raw),
+            'magic_hex'     => bin2hex(substr($raw, 0, 8)),
+            'magic_ascii'   => preg_replace('/[^\x20-\x7E]/', '.', substr($raw, 0, 16)),
+            'steps'         => [],
+            'decoded'       => null,
+            'is_serialized' => false,
+            'is_json'       => false,
+            'json_preview'  => null,
+        ];
+
+        $isJson = static function (string $s): bool {
+            $t = ltrim($s);
+            return $t !== '' && ($t[0] === '{' || $t[0] === '[');
+        };
+
+        // Centralized tolerant unserialize with typed-props preprocessing
+        $tryUnserializeTolerant = function (string $s, string $label) use (&$r) {
+            $ok = false; $val = null; $err = null; $relaxed = false;
+
+            // Ensure legacy aliases and coerce numeric strings before unserialize
+            try {
+                CourseArchiver::ensureLegacyAliases();
+            } catch (\Throwable) { /* ignore */ }
+
+            try {
+                $s = CourseArchiver::preprocessSerializedPayloadForTypedProps($s);
+            } catch (\Throwable) { /* ignore */ }
+
+            // Strict mode
+            set_error_handler(static function(){});
+            try {
+                $val = @unserialize($s, ['allowed_classes' => true]);
+                $ok  = ($val !== false) || (trim($s) === 'b:0;');
+            } catch (\Throwable $e) {
+                $err = $e->getMessage();
+                $ok  = false;
+            } finally {
+                restore_error_handler();
+            }
+            $r['steps'][] = ['action' => "unserialize[$label][strict]", 'ok' => $ok, 'error' => $err];
+
+            // Relaxed fallback (no class instantiation) + deincomplete to stdClass
+            if (!$ok) {
+                $err2 = null;
+                set_error_handler(static function(){});
+                try {
+                    $tmp = @unserialize($s, ['allowed_classes' => false]);
+                    if ($tmp !== false || trim($s) === 'b:0;') {
+                        $val = $this->deincomplete($tmp);
+                        $ok  = true;
+                        $relaxed = true;
+                        $err = null;
+                    }
+                } catch (\Throwable $e2) {
+                    $err2 = $e2->getMessage();
+                } finally {
+                    restore_error_handler();
+                }
+                $r['steps'][] = ['action' => "unserialize[$label][relaxed]", 'ok' => $ok, 'error' => $err2];
+            }
+
+            if ($ok) {
+                $r['is_serialized'] = true;
+                $r['decoded'] = null; // keep payload minimal
+                $r['used_relaxed'] = $relaxed;
+                return $val;
+            }
+            return null;
+        };
+
+        // 0) JSON as-is?
+        if ($isJson($raw)) {
+            $r['encoding'] = 'json';
+            $r['is_json']  = true;
+            $r['json_preview'] = json_decode($raw, true, 512, JSON_PARTIAL_OUTPUT_ON_ERROR);
+
+            return $r;
+        }
+
+        // Direct PHP serialize (strict then relaxed, after preprocessing)
+        if (($u = $tryUnserializeTolerant($raw, 'raw')) !== null) {
+            $r['encoding'] = 'php-serialize';
+            return $r + ['value' => $u];
+        }
+
+        // GZIP
+        if (strncmp($raw, "\x1F\x8B", 2) === 0) {
+            $dec = @gzdecode($raw);
+            $r['steps'][] = ['action' => 'gzdecode', 'ok' => $dec !== false];
+            if ($dec !== false) {
+                if ($isJson($dec)) {
+                    $r['encoding'] = 'gzip+json';
+                    $r['is_json']  = true;
+                    $r['json_preview'] = json_decode($dec, true, 512, JSON_PARTIAL_OUTPUT_ON_ERROR);
+                    return $r;
+                }
+                if (($u = $tryUnserializeTolerant($dec, 'gzip')) !== null) {
+                    $r['encoding'] = 'gzip+php-serialize';
+                    return $r + ['value' => $u];
+                }
+            }
+        }
+
+        // ZLIB/DEFLATE
+        $z2 = substr($raw, 0, 2);
+        if ($z2 === "\x78\x9C" || $z2 === "\x78\xDA") {
+            $dec = @gzuncompress($raw);
+            $r['steps'][] = ['action' => 'gzuncompress', 'ok' => $dec !== false];
+            if ($dec !== false) {
+                if ($isJson($dec)) {
+                    $r['encoding'] = 'zlib+json';
+                    $r['is_json']  = true;
+                    $r['json_preview'] = json_decode($dec, true, 512, JSON_PARTIAL_OUTPUT_ON_ERROR);
+                    return $r;
+                }
+                if (($u = $tryUnserializeTolerant($dec, 'zlib')) !== null) {
+                    $r['encoding'] = 'zlib+php-serialize';
+                    return $r + ['value' => $u];
+                }
+            }
+            $dec2 = @gzinflate($raw);
+            $r['steps'][] = ['action' => 'gzinflate', 'ok' => $dec2 !== false];
+            if ($dec2 !== false) {
+                if ($isJson($dec2)) {
+                    $r['encoding'] = 'deflate+json';
+                    $r['is_json']  = true;
+                    $r['json_preview'] = json_decode($dec2, true, 512, JSON_PARTIAL_OUTPUT_ON_ERROR);
+                    return $r;
+                }
+                if (($u = $tryUnserializeTolerant($dec2, 'deflate')) !== null) {
+                    $r['encoding'] = 'deflate+php-serialize';
+                    return $r + ['value' => $u];
+                }
+            }
+        }
+
+        // BASE64 (e.g. "Tzo0ODoi..." -> base64('O:48:"Chamilo...'))
+        if (preg_match('~^[A-Za-z0-9+/=\r\n]+$~', $raw)) {
+            $dec = base64_decode($raw, true);
+            $r['steps'][] = ['action' => 'base64_decode', 'ok' => $dec !== false];
+            if ($dec !== false) {
+                if ($isJson($dec)) {
+                    $r['encoding'] = 'base64(json)';
+                    $r['is_json']  = true;
+                    $r['json_preview'] = json_decode($dec, true, 512, JSON_PARTIAL_OUTPUT_ON_ERROR);
+                    return $r;
+                }
+                if (($u = $tryUnserializeTolerant($dec, 'base64')) !== null) {
+                    $r['encoding'] = 'base64(php-serialize)';
+                    return $r + ['value' => $u];
+                }
+                // base64 + gzip nested
+                if (strncmp($dec, "\x1F\x8B", 2) === 0) {
+                    $dec2 = @gzdecode($dec);
+                    $r['steps'][] = ['action' => 'base64+gzdecode', 'ok' => $dec2 !== false];
+                    if ($dec2 !== false && ($u = $tryUnserializeTolerant($dec2, 'base64+gzip')) !== null) {
+                        $r['encoding'] = 'base64(gzip+php-serialize)';
+                        return $r + ['value' => $u];
+                    }
+                }
+            }
+        }
+
+        // Nested ZIP?
+        if (strncmp($raw, "PK\x03\x04", 4) === 0) {
+            $r['encoding'] = 'nested-zip';
+        }
+
+        return $r;
+    }
+
+    /**
+     * Replace any __PHP_Incomplete_Class instances with stdClass (deep).
+     * Also traverses arrays and objects (diagnostics-only).
+     */
+    private function deincomplete(mixed $v): mixed
+    {
+        if ($v instanceof \__PHP_Incomplete_Class) {
+            $o = new \stdClass();
+            foreach (get_object_vars($v) as $k => $vv) {
+                $o->{$k} = $this->deincomplete($vv);
+            }
+            return $o;
+        }
+        if (is_array($v)) {
+            foreach ($v as $k => $vv) {
+                $v[$k] = $this->deincomplete($vv);
+            }
+            return $v;
+        }
+        if (is_object($v)) {
+            foreach (get_object_vars($v) as $k => $vv) {
+                $v->{$k} = $this->deincomplete($vv);
+            }
+            return $v;
+        }
+        return $v;
+    }
+
+    /**
+     * Return [ok, name, index, size, data] for the first matching entry of course_info.dat (case-insensitive).
+     * Also tries common subpaths, e.g., "course/course_info.dat".
+     */
+    private function readCourseInfoFromZip(string $zipPath): array
+    {
+        $candidates = [
+            'course_info.dat',
+            'course/course_info.dat',
+            'backup/course_info.dat',
+        ];
+
+        $zip = new \ZipArchive();
+        if (true !== ($err = $zip->open($zipPath))) {
+            return ['ok' => false, 'error' => 'Failed to open ZIP (ZipArchive::open error '.$err.')'];
+        }
+
+        // First: direct name lookup (case-insensitive)
+        $foundIdx = null;
+        $foundName = null;
+
+        for ($i = 0; $i < $zip->numFiles; $i++) {
+            $st = $zip->statIndex($i);
+            if (!$st || !isset($st['name'])) { continue; }
+            $name = (string) $st['name'];
+            $base = strtolower(basename($name));
+            if ($base === 'course_info.dat') {
+                $foundIdx = $i;
+                $foundName = $name;
+                break;
+            }
+        }
+
+        // Try specific candidate paths if direct scan failed
+        if ($foundIdx === null) {
+            foreach ($candidates as $cand) {
+                $idx = $zip->locateName($cand, \ZipArchive::FL_NOCASE);
+                if ($idx !== false) {
+                    $foundIdx = $idx;
+                    $foundName = $zip->getNameIndex($idx);
+                    break;
+                }
+            }
+        }
+
+        if ($foundIdx === null) {
+            // Build a short listing for debugging
+            $list = [];
+            $limit = min($zip->numFiles, 200);
+            for ($i = 0; $i < $limit; $i++) {
+                $n = $zip->getNameIndex($i);
+                if ($n !== false) { $list[] = $n; }
+            }
+            $zip->close();
+
+            return [
+                'ok' => false,
+                'error' => 'course_info.dat not found in archive',
+                'zip_list_sample' => $list,
+                'num_files' => $zip->numFiles,
+            ];
+        }
+
+        $stat = $zip->statIndex($foundIdx);
+        $size = (int) ($stat['size'] ?? 0);
+        $fp   = $zip->getStream($foundName);
+        if (!$fp) {
+            $zip->close();
+            return ['ok' => false, 'error' => 'Failed to open stream for course_info.dat (getStream)'];
+        }
+
+        $data = stream_get_contents($fp);
+        fclose($fp);
+        $zip->close();
+
+        if (!is_string($data)) {
+            return ['ok' => false, 'error' => 'Failed to read course_info.dat contents'];
+        }
+
+        return [
+            'ok'        => true,
+            'name'      => $foundName,
+            'index'     => $foundIdx,
+            'size'      => $size,
+            'data'      => $data,
+        ];
+    }
 
     /**
      * Copies the dependencies (document, link, quiz, etc.) to $course->resources
@@ -1156,6 +1660,123 @@ private function buildResourceTreeForVue(object $course): array
 
         $tree = [];
 
+        if (!empty($resources['document']) && \is_array($resources['document'])) {
+            $docs = $resources['document'];
+
+            $normalize = function (string $rawPath, string $title, string $filetype): string {
+                $p = trim($rawPath, '/');
+                $p = (string) preg_replace('~^(?:document/)+~i', '', $p);
+                $parts = array_values(array_filter(explode('/', $p), 'strlen'));
+
+                // host
+                if (!empty($parts) && ($parts[0] === 'localhost' || str_contains($parts[0], '.'))) {
+                    array_shift($parts);
+                }
+                // course-code
+                if (!empty($parts) && preg_match('~^[A-Z0-9_-]{6,}$~', $parts[0])) {
+                    array_shift($parts);
+                }
+
+                $clean = implode('/', $parts);
+                if ($clean === '' && $filetype !== 'folder') {
+                    $clean = $title;
+                }
+                if ($filetype === 'folder') {
+                    $clean = rtrim($clean, '/').'/';
+                }
+                return $clean;
+            };
+
+            $folderIdByPath = [];
+            foreach ($docs as $obj) {
+                if (!\is_object($obj)) { continue; }
+                $ft = (string)($obj->filetype ?? $obj->file_type ?? '');
+                if ($ft !== 'folder') { continue; }
+                $rel = $normalize((string)$obj->path, (string)$obj->title, $ft);
+                $key = rtrim($rel, '/');
+                if ($key !== '') {
+                    $folderIdByPath[strtolower($key)] = (int) $obj->source_id;
+                }
+            }
+
+            $docRoot = [];
+            $findChild = static function (array &$children, string $label): ?int {
+                foreach ($children as $i => $n) {
+                    if ((string)($n['label'] ?? '') === $label) { return $i; }
+                }
+                return null;
+            };
+
+            foreach ($docs as $obj) {
+                if (!\is_object($obj)) { continue; }
+
+                $title    = (string) $obj->title;
+                $filetype = (string) ($obj->filetype ?? $obj->file_type ?? '');
+                $rel      = $normalize((string) $obj->path, $title, $filetype);
+                $parts    = array_values(array_filter(explode('/', trim($rel, '/')), 'strlen'));
+
+                $cursor =& $docRoot;
+                $soFar = '';
+                $total = \count($parts);
+
+                for ($i = 0; $i < $total; $i++) {
+                    $seg      = $parts[$i];
+                    $isLast   = ($i === $total - 1);
+                    $isFolder = (!$isLast) || ($filetype === 'folder');
+
+                    $soFar = ltrim($soFar.'/'.$seg, '/');
+                    $label = $seg . ($isFolder ? '/' : '');
+
+                    $idx = $findChild($cursor, $label);
+                    if ($idx === null) {
+                        if ($isFolder) {
+                            $folderId = $folderIdByPath[strtolower($soFar)] ?? null;
+                            $node = [
+                                'id'         => $folderId ?? ('dir:'.$soFar),
+                                'label'      => $label,
+                                'selectable' => true,
+                                'children'   => [],
+                            ];
+                        } else {
+                            $node = [
+                                'id'         => (int) $obj->source_id,
+                                'label'      => $label,
+                                'selectable' => true,
+                            ];
+                        }
+                        $cursor[] = $node;
+                        $idx = \count($cursor) - 1;
+                    }
+
+                    if ($isFolder) {
+                        if (!isset($cursor[$idx]['children']) || !\is_array($cursor[$idx]['children'])) {
+                            $cursor[$idx]['children'] = [];
+                        }
+                        $cursor =& $cursor[$idx]['children'];
+                    }
+                }
+            }
+
+            $sortTree = null;
+            $sortTree = function (array &$nodes) use (&$sortTree) {
+                usort($nodes, static fn($a, $b) => strcasecmp((string)$a['label'], (string)$b['label']));
+                foreach ($nodes as &$n) {
+                    if (isset($n['children']) && \is_array($n['children'])) {
+                        $sortTree($n['children']);
+                    }
+                }
+            };
+            $sortTree($docRoot);
+
+            $tree[] = [
+                'type'     => 'document',
+                'title'    => $legacyTitles['document'] ?? ($fallbackTitles['document'] ?? 'Documents'),
+                'children' => $docRoot,
+            ];
+
+            $skipTypes['document'] = true;
+        }
+
         // Forums block
         $hasForumData =
             (!empty($resources['forum']) || !empty($resources['Forum']))
@@ -1186,12 +1807,10 @@ private function buildResourceTreeForVue(object $course): array
                 $course,
                 $legacyTitles['link'] ?? ($fallbackTitles['link'] ?? 'Links')
             );
-            // Prevent generic loop from adding separate "link" and "link_category" groups
             $skipTypes['link'] = true;
             $skipTypes['link_category'] = true;
         }
 
-        // Other tools
         foreach ($resources as $rawType => $items) {
             if (!\is_array($items) || empty($items)) {
                 continue;
@@ -1216,7 +1835,6 @@ private function buildResourceTreeForVue(object $course): array
                     'selectable' => true,
                 ];
                 $tree[] = $group;
-
                 continue;
             }
 
@@ -1235,21 +1853,7 @@ private function buildResourceTreeForVue(object $course): array
                 }
 
                 $label = $this->resolveItemLabel($typeKey, $obj, \is_int($idKey) ? $idKey : 0);
-                if ('document' === $typeKey) {
-                    $e = $this->objectEntity($obj);
-                    $rawPath = (string) ($e->path ?? '');
-                    if ('' !== $rawPath) {
-                        $rel = ltrim($rawPath, '/');
-                        $rel = preg_replace('~^document/?~', '', $rel);
-                        $filetype = (string) ($e->filetype ?? $e->file_type ?? '');
-                        if ('folder' === $filetype) {
-                            $rel = rtrim($rel, '/').'/';
-                        }
-                        if ('' !== $rel) {
-                            $label = $rel;
-                        }
-                    }
-                }
+
                 if ('tool_intro' === $typeKey && '#0' === $label && \is_string($idKey)) {
                     $label = $idKey;
                 }
@@ -1297,13 +1901,14 @@ private function buildResourceTreeForVue(object $course): array
         if ($this->debug) {
             $this->logDebug(
                 '[buildResourceTreeForVue] end groups',
-                array_map(fn ($g) => ['type' => $g['type'], 'items' => \count($g['items'] ?? [])], $tree)
+                array_map(fn ($g) => ['type' => $g['type'], 'items' => \count($g['items'] ?? []), 'children' => \count($g['children'] ?? [])], $tree)
             );
         }
 
         return $tree;
     }
 
+
     /**
      * Build forum tree (Category → Forum → Topic) for the UI.
      * Uses only "items" (no "children") and sets UI hints (has_children, item_count).
@@ -1315,54 +1920,37 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
         $res = \is_array($course->resources ?? null) ? $course->resources : [];
 
         // Buckets (defensive: accept legacy casings / aliases)
-        $catRaw = $res['forum_category'] ?? $res['Forum_Category'] ?? [];
-        $forumRaw = $res['forum'] ?? $res['Forum'] ?? [];
-        $topicRaw = $res['forum_topic'] ?? $res['ForumTopic'] ?? ($res['thread'] ?? []);
-        $postRaw = $res['forum_post'] ?? $res['Forum_Post'] ?? ($res['post'] ?? []);
+        $catRaw   = $res['forum_category'] ?? $res['Forum_Category'] ?? [];
+        $forumRaw = $res['forum']          ?? $res['Forum']          ?? [];
+        $topicRaw = $res['forum_topic']    ?? $res['ForumTopic']     ?? ($res['thread'] ?? []);
+        $postRaw  = $res['forum_post']     ?? $res['Forum_Post']     ?? ($res['post'] ?? []);
 
         $this->logDebug('[buildForumTreeForVue] raw counts', [
             'categories' => \is_array($catRaw) ? \count($catRaw) : 0,
-            'forums' => \is_array($forumRaw) ? \count($forumRaw) : 0,
-            'topics' => \is_array($topicRaw) ? \count($topicRaw) : 0,
-            'posts' => \is_array($postRaw) ? \count($postRaw) : 0,
+            'forums'     => \is_array($forumRaw) ? \count($forumRaw) : 0,
+            'topics'     => \is_array($topicRaw) ? \count($topicRaw) : 0,
+            'posts'      => \is_array($postRaw) ? \count($postRaw) : 0,
         ]);
 
         // Quick classifiers (defensive)
         $isForum = function (object $o): bool {
             $e = (isset($o->obj) && \is_object($o->obj)) ? $o->obj : $o;
-            if (isset($e->forum_title) && \is_string($e->forum_title)) {
-                return true;
-            }
-            if (isset($e->default_view) || isset($e->allow_anonymous)) {
-                return true;
-            }
-            if ((isset($e->forum_category) || isset($e->forum_category_id) || isset($e->category_id)) && !isset($e->forum_id)) {
-                return true;
-            }
-
+            if (isset($e->forum_title) && \is_string($e->forum_title)) { return true; }
+            if (isset($e->default_view) || isset($e->allow_anonymous)) { return true; }
+            if ((isset($e->forum_category) || isset($e->forum_category_id) || isset($e->category_id)) && !isset($e->forum_id)) { return true; }
             return false;
         };
         $isTopic = function (object $o): bool {
             $e = (isset($o->obj) && \is_object($o->obj)) ? $o->obj : $o;
-            if (isset($e->forum_id) && (isset($e->thread_title) || isset($e->thread_date) || isset($e->poster_name))) {
-                return true;
-            }
-            if (isset($e->forum_id) && !isset($e->forum_title)) {
-                return true;
-            }
-
+            if (isset($e->forum_id) && (isset($e->thread_title) || isset($e->thread_date) || isset($e->poster_name))) { return true; }
+            if (isset($e->forum_id) && !isset($e->forum_title)) { return true; }
             return false;
         };
         $getForumCategoryId = function (object $forum): int {
             $e = (isset($forum->obj) && \is_object($forum->obj)) ? $forum->obj : $forum;
             $cid = (int) ($e->forum_category ?? 0);
-            if ($cid <= 0) {
-                $cid = (int) ($e->forum_category_id ?? 0);
-            }
-            if ($cid <= 0) {
-                $cid = (int) ($e->category_id ?? 0);
-            }
-
+            if ($cid <= 0) { $cid = (int) ($e->forum_category_id ?? 0); }
+            if ($cid <= 0) { $cid = (int) ($e->category_id ?? 0); }
             return $cid;
         };
 
@@ -1370,33 +1958,32 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
         $cats = [];
         foreach ($catRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             $label = $this->resolveItemLabel('forum_category', $this->objectEntity($obj), $id);
             $cats[$id] = [
-                'id' => $id,
-                'type' => 'forum_category',
-                'label' => $label,
-                'selectable' => false,
-                'items' => [],
-                // UI hints
+                'id'         => $id,
+                'type'       => 'forum_category',
+                'label'      => ($label !== '' ? $label : 'Category #'.$id).'/',
+                'selectable' => true,
+                'items'      => [],
                 'has_children' => false,
-                'item_count' => 0,
+                'item_count'   => 0,
+                'extra'      => ['filetype' => 'folder'],
             ];
         }
         // Virtual "Uncategorized"
         $uncatKey = -9999;
         if (!isset($cats[$uncatKey])) {
             $cats[$uncatKey] = [
-                'id' => $uncatKey,
-                'type' => 'forum_category',
-                'label' => 'Uncategorized',
-                'selectable' => false,
-                'items' => [],
-                '_virtual' => true,
+                'id'           => $uncatKey,
+                'type'         => 'forum_category',
+                'label'        => 'Uncategorized/',
+                'selectable'   => true,
+                'items'        => [],
+                '_virtual'     => true,
                 'has_children' => false,
-                'item_count' => 0,
+                'item_count'   => 0,
+                'extra'        => ['filetype' => 'folder'],
             ];
         }
 
@@ -1404,12 +1991,9 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
         $forums = [];
         foreach ($forumRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             if (!$isForum($obj)) {
                 $this->logDebug('[buildForumTreeForVue] skipped non-forum in forum bucket', ['id' => $id]);
-
                 continue;
             }
             $forums[$id] = $this->objectEntity($obj);
@@ -1420,82 +2004,61 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
         $postCountByTopic = [];
         foreach ($topicRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             if ($isForum($obj) && !$isTopic($obj)) {
                 $this->logDebug('[buildForumTreeForVue] WARNING: forum object found in topic bucket; skipping', ['id' => $id]);
-
-                continue;
-            }
-            if (!$isTopic($obj)) {
                 continue;
             }
+            if (!$isTopic($obj)) { continue; }
             $topics[$id] = $this->objectEntity($obj);
         }
         foreach ($postRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             $e = $this->objectEntity($obj);
             $tid = (int) ($e->thread_id ?? 0);
-            if ($tid > 0) {
-                $postCountByTopic[$tid] = ($postCountByTopic[$tid] ?? 0) + 1;
-            }
+            if ($tid > 0) { $postCountByTopic[$tid] = ($postCountByTopic[$tid] ?? 0) + 1; }
         }
 
         // Attach topics to forums and forums to categories
         foreach ($forums as $fid => $f) {
             $catId = $getForumCategoryId($f);
-            if (!isset($cats[$catId])) {
-                $catId = $uncatKey;
-            }
+            if (!isset($cats[$catId])) { $catId = $uncatKey; }
 
             $forumNode = [
-                'id' => $fid,
-                'type' => 'forum',
-                'label' => $this->resolveItemLabel('forum', $f, $fid),
-                'extra' => $this->buildExtra('forum', $f) ?: new stdClass(),
+                'id'         => $fid,
+                'type'       => 'forum',
+                'label'      => $this->resolveItemLabel('forum', $f, $fid),
+                'extra'      => $this->buildExtra('forum', $f) ?: new \stdClass(),
                 'selectable' => true,
-                'items' => [],
+                'items'      => [],
                 // UI hints
                 'has_children' => false,
-                'item_count' => 0,
-                'ui_depth' => 2,
+                'item_count'   => 0,
+                'ui_depth'     => 2,
             ];
 
             foreach ($topics as $tid => $t) {
-                if ((int) ($t->forum_id ?? 0) !== $fid) {
-                    continue;
-                }
+                if ((int) ($t->forum_id ?? 0) !== $fid) { continue; }
 
-                $author = (string) ($t->thread_poster_name ?? $t->poster_name ?? '');
-                $date = (string) ($t->thread_date ?? '');
-                $nPosts = (int) ($postCountByTopic[$tid] ?? 0);
+                $author  = (string) ($t->thread_poster_name ?? $t->poster_name ?? '');
+                $date    = (string) ($t->thread_date ?? '');
+                $nPosts  = (int) ($postCountByTopic[$tid] ?? 0);
 
                 $topicLabel = $this->resolveItemLabel('forum_topic', $t, $tid);
                 $meta = [];
-                if ('' !== $author) {
-                    $meta[] = $author;
-                }
-                if ('' !== $date) {
-                    $meta[] = $date;
-                }
-                if ($meta) {
-                    $topicLabel .= ' ('.implode(', ', $meta).')';
-                }
-                if ($nPosts > 0) {
-                    $topicLabel .= ' — '.$nPosts.' post'.(1 === $nPosts ? '' : 's');
-                }
+                if ($author !== '') { $meta[] = $author; }
+                if ($date   !== '') { $meta[] = $date; }
+                if ($meta) { $topicLabel .= ' ('.implode(', ', $meta).')'; }
+                if ($nPosts > 0) { $topicLabel .= ' — '.$nPosts.' post'.(1 === $nPosts ? '' : 's'); }
 
                 $forumNode['items'][] = [
-                    'id' => $tid,
-                    'type' => 'forum_topic',
-                    'label' => $topicLabel,
-                    'extra' => new stdClass(),
+                    'id'         => $tid,
+                    'type'       => 'forum_topic',
+                    'label'      => $topicLabel,
+                    'extra'      => new \stdClass(),
                     'selectable' => true,
-                    'ui_depth' => 3,
+                    'ui_depth'   => 3,
                     'item_count' => 0,
                 ];
             }
@@ -1503,7 +2066,7 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
             if (!empty($forumNode['items'])) {
                 usort($forumNode['items'], static fn ($a, $b) => strcasecmp((string) $a['label'], (string) $b['label']));
                 $forumNode['has_children'] = true;
-                $forumNode['item_count'] = \count($forumNode['items']);
+                $forumNode['item_count']   = \count($forumNode['items']);
             }
 
             $cats[$catId]['items'][] = $forumNode;
@@ -1511,10 +2074,7 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
 
         // Remove empty virtual category; sort forums inside each category
         $catNodes = array_values(array_filter($cats, static function ($c) {
-            if (!empty($c['_virtual']) && empty($c['items'])) {
-                return false;
-            }
-
+            if (!empty($c['_virtual']) && empty($c['items'])) { return false; }
             return true;
         }));
 
@@ -1523,9 +2083,7 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
             if (!empty($cat['items'])) {
                 $lift = [];
                 foreach ($cat['items'] as &$forumNode) {
-                    if (($forumNode['type'] ?? '') !== 'forum' || empty($forumNode['items'])) {
-                        continue;
-                    }
+                    if (($forumNode['type'] ?? '') !== 'forum' || empty($forumNode['items'])) { continue; }
                     $keep = [];
                     foreach ($forumNode['items'] as $child) {
                         if (($child['type'] ?? '') === 'forum') {
@@ -1533,34 +2091,32 @@ private function buildForumTreeForVue(object $course, string $groupTitle): array
                             $this->logDebug('[buildForumTreeForVue] flatten: lifted nested forum', [
                                 'parent_forum_id' => $forumNode['id'] ?? null,
                                 'lifted_forum_id' => $child['id'] ?? null,
-                                'cat_id' => $cat['id'] ?? null,
+                                'cat_id'          => $cat['id'] ?? null,
                             ]);
                         } else {
                             $keep[] = $child;
                         }
                     }
-                    $forumNode['items'] = $keep;
+                    $forumNode['items']        = $keep;
                     $forumNode['has_children'] = !empty($keep);
-                    $forumNode['item_count'] = \count($keep);
+                    $forumNode['item_count']   = \count($keep);
                 }
                 unset($forumNode);
 
-                foreach ($lift as $n) {
-                    $cat['items'][] = $n;
-                }
+                foreach ($lift as $n) { $cat['items'][] = $n; }
                 usort($cat['items'], static fn ($a, $b) => strcasecmp((string) $a['label'], (string) $b['label']));
             }
 
             // UI hints for category
             $cat['has_children'] = !empty($cat['items']);
-            $cat['item_count'] = \count($cat['items'] ?? []);
+            $cat['item_count']   = \count($cat['items'] ?? []);
         }
         unset($cat);
 
         $this->logDebug('[buildForumTreeForVue] end', ['categories' => \count($catNodes)]);
 
         return [
-            'type' => 'forum',
+            'type'  => 'forum',
             'title' => $groupTitle,
             'items' => $catNodes,
         ];
@@ -1917,6 +2473,10 @@ private function firstExistingKey(array $orig, array $candidates): ?string
      */
     private function filterLegacyCourseBySelection(object $course, array $selected): object
     {
+        // Sanitize incoming selection (frontend sometimes sends synthetic groups)
+        $selected = array_filter($selected, 'is_array');
+        unset($selected['undefined']);
+
         $this->logDebug('[filterSelection] start', ['selected_types' => array_keys($selected)]);
 
         if (empty($course->resources) || !\is_array($course->resources)) {
@@ -1928,7 +2488,7 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
         /** @var array<string,mixed> $orig */
         $orig = $course->resources;
 
-        // Keep meta buckets (keys starting with "__") so we don't lose import_source, etc.
+        // Preserve meta buckets (keys that start with "__")
         $__metaBuckets = [];
         foreach ($orig as $k => $v) {
             if (\is_string($k) && str_starts_with($k, '__')) {
@@ -1936,15 +2496,17 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
             }
         }
 
-        $getBucket = static function (array $a, string $key): array {
-            return (isset($a[$key]) && \is_array($a[$key])) ? $a[$key] : [];
-        };
+        $getBucket = fn (array $a, string $key): array => (isset($a[$key]) && \is_array($a[$key])) ? $a[$key] : [];
 
-        // Forums flow
-        if (!empty($selected) && !empty($selected['forum'])) {
+        // ---------- Forums flow ----------
+        if (!empty($selected['forum'])) {
             $selForums = array_fill_keys(array_map('strval', array_keys($selected['forum'])), true);
             if (!empty($selForums)) {
-                $forums = $getBucket($orig, 'forum');
+                // tolerant lookups
+                $forums  = $this->findBucket($orig, 'forum');
+                $threads = $this->findBucket($orig, 'forum_topic');
+                $posts   = $this->findBucket($orig, 'forum_post');
+
                 $catsToKeep = [];
 
                 foreach ($forums as $fid => $f) {
@@ -1952,13 +2514,12 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                         continue;
                     }
                     $e = (isset($f->obj) && \is_object($f->obj)) ? $f->obj : $f;
-                    $cid = (int) ($e->forum_category ?? 0);
+                    $cid = (int) ($e->forum_category ?? $e->forum_category_id ?? $e->category_id ?? 0);
                     if ($cid > 0) {
                         $catsToKeep[$cid] = true;
                     }
                 }
 
-                $threads = $getBucket($orig, 'thread');
                 $threadToKeep = [];
                 foreach ($threads as $tid => $t) {
                     $e = (isset($t->obj) && \is_object($t->obj)) ? $t->obj : $t;
@@ -1967,7 +2528,6 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                     }
                 }
 
-                $posts = $getBucket($orig, 'post');
                 $postToKeep = [];
                 foreach ($posts as $pid => $p) {
                     $e = (isset($p->obj) && \is_object($p->obj)) ? $p->obj : $p;
@@ -1981,61 +2541,61 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                     if (!\is_array($ids) || empty($ids)) {
                         continue;
                     }
-                    $bucket = $getBucket($orig, (string) $type);
-                    if (!empty($bucket)) {
+                    $bucket = $this->findBucket($orig, (string) $type);
+                    $key    = $this->findBucketKey($orig, (string) $type);
+                    if ($key !== null && !empty($bucket)) {
                         $idsMap = array_fill_keys(array_map('strval', array_keys($ids)), true);
-                        $out[$type] = array_intersect_key($bucket, $idsMap);
+                        $out[$key] = $this->intersectBucketByIds($bucket, $idsMap);
                     }
                 }
 
-                $forumCat = $getBucket($orig, 'Forum_Category');
-                if (!empty($forumCat)) {
-                    $out['Forum_Category'] = array_intersect_key(
-                        $forumCat,
-                        array_fill_keys(array_map('strval', array_keys($catsToKeep)), true)
-                    );
+                $forumCat     = $this->findBucket($orig, 'forum_category');
+                $forumBucket  = $this->findBucket($orig, 'forum');
+                $threadBucket = $this->findBucket($orig, 'forum_topic');
+                $postBucket   = $this->findBucket($orig, 'forum_post');
+
+                if (!empty($forumCat) && !empty($catsToKeep)) {
+                    $out[$this->findBucketKey($orig, 'forum_category') ?? 'Forum_Category'] =
+                        array_intersect_key(
+                            $forumCat,
+                            array_fill_keys(array_map('strval', array_keys($catsToKeep)), true)
+                        );
                 }
 
-                $forumBucket = $getBucket($orig, 'forum');
                 if (!empty($forumBucket)) {
-                    $out['forum'] = array_intersect_key($forumBucket, $selForums);
+                    $out[$this->findBucketKey($orig, 'forum') ?? 'forum'] =
+                        array_intersect_key($forumBucket, $selForums);
                 }
-
-                $threadBucket = $getBucket($orig, 'thread');
                 if (!empty($threadBucket)) {
-                    $out['thread'] = array_intersect_key(
-                        $threadBucket,
-                        array_fill_keys(array_map('strval', array_keys($threadToKeep)), true)
-                    );
+                    $out[$this->findBucketKey($orig, 'forum_topic') ?? 'thread'] =
+                        array_intersect_key(
+                            $threadBucket,
+                            array_fill_keys(array_map('strval', array_keys($threadToKeep)), true)
+                        );
                 }
-
-                $postBucket = $getBucket($orig, 'post');
                 if (!empty($postBucket)) {
-                    $out['post'] = array_intersect_key(
-                        $postBucket,
-                        array_fill_keys(array_map('strval', array_keys($postToKeep)), true)
-                    );
+                    $out[$this->findBucketKey($orig, 'forum_post') ?? 'post'] =
+                        array_intersect_key(
+                            $postBucket,
+                            array_fill_keys(array_map('strval', array_keys($postToKeep)), true)
+                        );
                 }
 
+                // If we have forums but no Forum_Category (edge), keep original categories
                 if (!empty($out['forum']) && empty($out['Forum_Category']) && !empty($forumCat)) {
                     $out['Forum_Category'] = $forumCat;
                 }
 
-                // Preserve meta buckets
-                if (!empty($__metaBuckets)) {
-                    $out = array_filter($out);
-                    $course->resources = $__metaBuckets + $out;
-                } else {
-                    $course->resources = array_filter($out);
-                }
+                $out = array_filter($out);
+                $course->resources = !empty($__metaBuckets) ? ($__metaBuckets + $out) : $out;
 
-                $this->logDebug('[filterSelection] end', [
+                $this->logDebug('[filterSelection] end (forums)', [
                     'kept_types' => array_keys($course->resources),
                     'forum_counts' => [
                         'Forum_Category' => \is_array($course->resources['Forum_Category'] ?? null) ? \count($course->resources['Forum_Category']) : 0,
-                        'forum' => \is_array($course->resources['forum'] ?? null) ? \count($course->resources['forum']) : 0,
-                        'thread' => \is_array($course->resources['thread'] ?? null) ? \count($course->resources['thread']) : 0,
-                        'post' => \is_array($course->resources['post'] ?? null) ? \count($course->resources['post']) : 0,
+                        'forum'          => \is_array($course->resources['forum'] ?? null) ? \count($course->resources['forum']) : 0,
+                        'thread'         => \is_array($course->resources['thread'] ?? null) ? \count($course->resources['thread']) : 0,
+                        'post'           => \is_array($course->resources['post'] ?? null) ? \count($course->resources['post']) : 0,
                     ],
                 ]);
 
@@ -2043,30 +2603,24 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
             }
         }
 
-        // Generic + quiz/survey/gradebook flows
-        $alias = [
-            'tool_intro' => 'Tool introduction',
-        ];
-
+        // ---------- Generic + quiz/survey/gradebook ----------
         $keep = [];
         foreach ($selected as $type => $ids) {
             if (!\is_array($ids) || empty($ids)) {
                 continue;
             }
-
-            $legacyKey = $type;
-            if (!isset($orig[$legacyKey]) && isset($alias[$type])) {
-                $legacyKey = $alias[$type];
+            $legacyKey = $this->findBucketKey($orig, (string) $type);
+            if ($legacyKey === null) {
+                continue;
             }
-
-            $bucket = $getBucket($orig, (string) $legacyKey);
-            if (!empty($bucket)) {
+            $bucket = $orig[$legacyKey] ?? [];
+            if (!empty($bucket) && \is_array($bucket)) {
                 $idsMap = array_fill_keys(array_map('strval', array_keys($ids)), true);
-                $keep[$legacyKey] = array_intersect_key($bucket, $idsMap);
+                $keep[$legacyKey] = $this->intersectBucketByIds($bucket, $idsMap);
             }
         }
 
-        // Gradebook bucket
+        // Gradebook
         $gbKey = $this->firstExistingKey($orig, ['gradebook', 'Gradebook', 'GradebookBackup', 'gradebookbackup']);
         if ($gbKey && !empty($selected['gradebook'])) {
             $gbBucket = $getBucket($orig, $gbKey);
@@ -2076,18 +2630,18 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
 
                 if (\in_array('all', $selIds, true) || !\is_object($firstItem)) {
                     $keep[$gbKey] = $gbBucket;
-                    $this->logDebug('[filterSelection] kept full gradebook bucket', ['key' => $gbKey, 'count' => \count($gbBucket)]);
+                    $this->logDebug('[filterSelection] kept full gradebook', ['key' => $gbKey, 'count' => \count($gbBucket)]);
                 } else {
                     $keep[$gbKey] = array_intersect_key($gbBucket, array_fill_keys(array_map('strval', $selIds), true));
-                    $this->logDebug('[filterSelection] kept partial gradebook bucket', ['key' => $gbKey, 'count' => \count($keep[$gbKey])]);
+                    $this->logDebug('[filterSelection] kept partial gradebook', ['key' => $gbKey, 'count' => \count($keep[$gbKey])]);
                 }
             }
         }
 
-        // Quizzes → questions (+ images)
-        $quizKey = $this->firstExistingKey($orig, ['quiz', 'Quiz']);
+        // Quizzes -> questions (+ images)
+        $quizKey = $this->firstExistingKey($orig, ['quiz','Quiz']);
         if ($quizKey && !empty($keep[$quizKey])) {
-            $questionKey = $this->firstExistingKey($orig, ['Exercise_Question', 'exercise_question', \defined('RESOURCE_QUIZQUESTION') ? RESOURCE_QUIZQUESTION : '']);
+            $questionKey = $this->firstExistingKey($orig, ['Exercise_Question','exercise_question', \defined('RESOURCE_QUIZQUESTION') ? RESOURCE_QUIZQUESTION : '']);
             if ($questionKey) {
                 $qids = [];
                 foreach ($keep[$quizKey] as $qid => $qwrap) {
@@ -2098,19 +2652,13 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                         }
                     }
                 }
-
                 if (!empty($qids)) {
                     $questionBucket = $getBucket($orig, $questionKey);
                     $selQ = array_intersect_key($questionBucket, $qids);
                     if (!empty($selQ)) {
                         $keep[$questionKey] = $selQ;
-                        $this->logDebug('[filterSelection] pulled question bucket for quizzes', [
-                            'quiz_count' => \count($keep[$quizKey]),
-                            'question_key' => $questionKey,
-                            'questions_kept' => \count($keep[$questionKey]),
-                        ]);
 
-                        $docKey = $this->firstExistingKey($orig, ['document', 'Document', \defined('RESOURCE_DOCUMENT') ? RESOURCE_DOCUMENT : '']);
+                        $docKey = $this->firstExistingKey($orig, ['document','Document', \defined('RESOURCE_DOCUMENT') ? RESOURCE_DOCUMENT : '']);
                         if ($docKey) {
                             $docBucket = $getBucket($orig, $docKey);
                             $imageQuizBucket = (isset($docBucket['image_quiz']) && \is_array($docBucket['image_quiz'])) ? $docBucket['image_quiz'] : [];
@@ -2126,27 +2674,24 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                                 if (!empty($needed)) {
                                     $keep[$docKey] = $keep[$docKey] ?? [];
                                     $keep[$docKey]['image_quiz'] = array_intersect_key($imageQuizBucket, $needed);
-                                    $this->logDebug('[filterSelection] included image_quiz docs for questions', [
-                                        'count' => \count($keep[$docKey]['image_quiz']),
-                                    ]);
                                 }
                             }
                         }
                     }
                 }
             } else {
-                $this->logDebug('[filterSelection] quizzes selected but no question bucket found in backup');
+                $this->logDebug('[filterSelection] quizzes selected but no question bucket found');
             }
         }
 
-        // Surveys → questions (+ invitations)
-        $surveyKey = $this->firstExistingKey($orig, ['survey', 'Survey']);
+        // Surveys -> questions (+ invitations)
+        $surveyKey = $this->firstExistingKey($orig, ['survey','Survey']);
         if ($surveyKey && !empty($keep[$surveyKey])) {
-            $surveyQuestionKey = $this->firstExistingKey($orig, ['Survey_Question', 'survey_question', \defined('RESOURCE_SURVEYQUESTION') ? RESOURCE_SURVEYQUESTION : '']);
-            $surveyInvitationKey = $this->firstExistingKey($orig, ['Survey_Invitation', 'survey_invitation', \defined('RESOURCE_SURVEYINVITATION') ? RESOURCE_SURVEYINVITATION : '']);
+            $surveyQuestionKey   = $this->firstExistingKey($orig, ['Survey_Question','survey_question', \defined('RESOURCE_SURVEYQUESTION') ? RESOURCE_SURVEYQUESTION : '']);
+            $surveyInvitationKey = $this->firstExistingKey($orig, ['Survey_Invitation','survey_invitation', \defined('RESOURCE_SURVEYINVITATION') ? RESOURCE_SURVEYINVITATION : '']);
 
             if ($surveyQuestionKey) {
-                $neededQids = [];
+                $neededQids   = [];
                 $selSurveyIds = array_map('strval', array_keys($keep[$surveyKey]));
 
                 foreach ($keep[$surveyKey] as $sid => $sWrap) {
@@ -2157,7 +2702,6 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                         }
                     }
                 }
-
                 if (empty($neededQids)) {
                     $surveyQBucket = $getBucket($orig, $surveyQuestionKey);
                     foreach ($surveyQBucket as $qid => $qWrap) {
@@ -2168,20 +2712,12 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                         }
                     }
                 }
-
                 if (!empty($neededQids)) {
                     $surveyQBucket = $getBucket($orig, $surveyQuestionKey);
                     $keep[$surveyQuestionKey] = array_intersect_key($surveyQBucket, $neededQids);
-                    $this->logDebug('[filterSelection] pulled question bucket for surveys', [
-                        'survey_count' => \count($keep[$surveyKey]),
-                        'question_key' => $surveyQuestionKey,
-                        'questions_kept' => \count($keep[$surveyQuestionKey]),
-                    ]);
-                } else {
-                    $this->logDebug('[filterSelection] surveys selected but no matching questions found');
                 }
             } else {
-                $this->logDebug('[filterSelection] surveys selected but no question bucket found in backup');
+                $this->logDebug('[filterSelection] surveys selected but no question bucket found');
             }
 
             if ($surveyInvitationKey) {
@@ -2197,15 +2733,13 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                     }
                     if (!empty($neededInv)) {
                         $keep[$surveyInvitationKey] = array_intersect_key($invBucket, $neededInv);
-                        $this->logDebug('[filterSelection] included survey invitations', [
-                            'invitations_kept' => \count($keep[$surveyInvitationKey]),
-                        ]);
                     }
                 }
             }
         }
 
-        $docKey = $this->firstExistingKey($orig, ['document', 'Document', \defined('RESOURCE_DOCUMENT') ? RESOURCE_DOCUMENT : '']);
+        // Documents: add parent folders for selected files
+        $docKey = $this->firstExistingKey($orig, ['document','Document', \defined('RESOURCE_DOCUMENT') ? RESOURCE_DOCUMENT : '']);
         if ($docKey && !empty($keep[$docKey])) {
             $docBucket = $getBucket($orig, $docKey);
 
@@ -2213,49 +2747,30 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
             foreach ($docBucket as $fid => $res) {
                 $e = (isset($res->obj) && \is_object($res->obj)) ? $res->obj : $res;
                 $ftRaw = strtolower((string) ($e->file_type ?? $e->filetype ?? ''));
-                $isFolder = ('folder' === $ftRaw);
-                if (!$isFolder) {
-                    $pTest = (string) ($e->path ?? '');
-                    if ('' !== $pTest) {
-                        $isFolder = ('/' === substr($pTest, -1));
-                    }
-                }
-                if (!$isFolder) {
-                    continue;
-                }
+                $isFolder = ('folder' === $ftRaw) || (isset($e->path) && substr((string) $e->path, -1) === '/');
+                if (!$isFolder) { continue; }
 
                 $p = (string) ($e->path ?? '');
-                if ('' === $p) {
-                    continue;
-                }
+                if ('' === $p) { continue; }
 
                 $frel = '/'.ltrim(substr($p, 8), '/');
                 $frel = rtrim($frel, '/').'/';
-                if ('//' !== $frel) {
-                    $foldersByRel[$frel] = $fid;
-                }
+                if ('//' !== $frel) { $foldersByRel[$frel] = $fid; }
             }
 
             $needFolderIds = [];
             foreach ($keep[$docKey] as $id => $res) {
                 $e = (isset($res->obj) && \is_object($res->obj)) ? $res->obj : $res;
-
                 $ftRaw = strtolower((string) ($e->file_type ?? $e->filetype ?? ''));
-                $isFolder = ('folder' === $ftRaw) || ('/' === substr((string) ($e->path ?? ''), -1));
-                if ($isFolder) {
-                    continue;
-                }
+                $isFolder = ('folder' === $ftRaw) || (isset($e->path) && substr((string) $e->path, -1) === '/');
+                if ($isFolder) { continue; }
 
                 $p = (string) ($e->path ?? '');
-                if ('' === $p) {
-                    continue;
-                }
+                if ('' === $p) { continue; }
 
                 $rel = '/'.ltrim(substr($p, 8), '/');
                 $dir = rtrim(\dirname($rel), '/');
-                if ('' === $dir) {
-                    continue;
-                }
+                if ('' === $dir) { continue; }
 
                 $acc = '';
                 foreach (array_filter(explode('/', $dir)) as $seg) {
@@ -2266,67 +2781,40 @@ private function filterLegacyCourseBySelection(object $course, array $selected):
                     }
                 }
             }
-
             if (!empty($needFolderIds)) {
                 $added = array_intersect_key($docBucket, $needFolderIds);
                 $keep[$docKey] += $added;
-
-                $this->logDebug('[filterSelection] added parent folders for selected documents', [
-                    'doc_key' => $docKey,
-                    'added_folders' => \count($added),
-                ]);
             }
         }
 
-        $lnkKey = $this->firstExistingKey(
-            $orig,
-            ['link', 'Link', \defined('RESOURCE_LINK') ? RESOURCE_LINK : '']
-        );
-
+        // Links -> pull categories used by the selected links
+        $lnkKey = $this->firstExistingKey($orig, ['link','Link', \defined('RESOURCE_LINK') ? RESOURCE_LINK : '']);
         if ($lnkKey && !empty($keep[$lnkKey])) {
             $catIdsUsed = [];
             foreach ($keep[$lnkKey] as $lid => $lWrap) {
                 $L = (isset($lWrap->obj) && \is_object($lWrap->obj)) ? $lWrap->obj : $lWrap;
                 $cid = (int) ($L->category_id ?? 0);
-                if ($cid > 0) {
-                    $catIdsUsed[(string) $cid] = true;
-                }
+                if ($cid > 0) { $catIdsUsed[(string) $cid] = true; }
             }
 
-            $catKey = $this->firstExistingKey(
-                $orig,
-                ['link_category', 'Link_Category', \defined('RESOURCE_LINKCATEGORY') ? (string) RESOURCE_LINKCATEGORY : '']
-            );
-
+            $catKey = $this->firstExistingKey($orig, ['link_category','Link_Category', \defined('RESOURCE_LINKCATEGORY') ? (string) RESOURCE_LINKCATEGORY : '']);
             if ($catKey && !empty($catIdsUsed)) {
                 $catBucket = $getBucket($orig, $catKey);
                 if (!empty($catBucket)) {
                     $subset = array_intersect_key($catBucket, $catIdsUsed);
                     $keep[$catKey] = $subset;
-                    $keep['link_category'] = $subset;
-
-                    $this->logDebug('[filterSelection] pulled link categories for selected links', [
-                        'link_key' => $lnkKey,
-                        'category_key' => $catKey,
-                        'links_kept' => \count($keep[$lnkKey]),
-                        'cats_kept' => \count($subset),
-                        'mirrored_to' => 'link_category',
-                    ]);
+                    $keep['link_category'] = $subset; // mirror for convenience
                 }
-            } else {
-                $this->logDebug('[filterSelection] link category bucket not found in backup');
             }
         }
 
         $keep = array_filter($keep);
-        if (!empty($__metaBuckets)) {
-            $course->resources = $__metaBuckets + $keep;
-        } else {
-            $course->resources = $keep;
-        }
+        $course->resources = !empty($__metaBuckets) ? ($__metaBuckets + $keep) : $keep;
 
         $this->logDebug('[filterSelection] non-forum flow end', [
-            'kept_types' => array_keys($course->resources),
+            'selected_types' => array_keys($selected),
+            'orig_types'     => array_keys($orig),
+            'kept_types'     => array_keys($course->resources ?? []),
         ]);
 
         return $course;
@@ -2534,31 +3022,29 @@ private function buildLinkTreeForVue(object $course, string $groupTitle): array
         $this->logDebug('[buildLinkTreeForVue] start');
 
         $res = \is_array($course->resources ?? null) ? $course->resources : [];
-        $catRaw = $res['link_category'] ?? $res['Link_Category'] ?? [];
-        $linkRaw = $res['link'] ?? $res['Link'] ?? [];
+        $catRaw  = $res['link_category'] ?? $res['Link_Category'] ?? [];
+        $linkRaw = $res['link']          ?? $res['Link']          ?? [];
 
         $this->logDebug('[buildLinkTreeForVue] raw counts', [
             'categories' => \is_array($catRaw) ? \count($catRaw) : 0,
-            'links' => \is_array($linkRaw) ? \count($linkRaw) : 0,
+            'links'      => \is_array($linkRaw) ? \count($linkRaw) : 0,
         ]);
 
         $cats = [];
         foreach ($catRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             $e = $this->objectEntity($obj);
             $label = $this->resolveItemLabel('link_category', $e, $id);
-
             $cats[$id] = [
-                'id' => $id,
-                'type' => 'link_category',
-                'label' => '' !== $label ? $label : ('Category #'.$id),
-                'selectable' => false,
-                'items' => [],
+                'id'           => $id,
+                'type'         => 'link_category',
+                'label'        => (($label !== '' ? $label : ('Category #'.$id)).'/'),
+                'selectable'   => true,
+                'items'        => [],
                 'has_children' => false,
-                'item_count' => 0,
+                'item_count'   => 0,
+                'extra'        => ['filetype' => 'folder'],
             ];
         }
 
@@ -2566,35 +3052,32 @@ private function buildLinkTreeForVue(object $course, string $groupTitle): array
         $uncatKey = -9999;
         if (!isset($cats[$uncatKey])) {
             $cats[$uncatKey] = [
-                'id' => $uncatKey,
-                'type' => 'link_category',
-                'label' => 'Uncategorized',
-                'selectable' => false,
-                'items' => [],
-                '_virtual' => true,
+                'id'           => $uncatKey,
+                'type'         => 'link_category',
+                'label'        => 'Uncategorized/',
+                'selectable'   => true,
+                'items'        => [],
+                '_virtual'     => true,
                 'has_children' => false,
-                'item_count' => 0,
+                'item_count'   => 0,
+                'extra'        => ['filetype' => 'folder'],
             ];
         }
 
         // Assign links to categories
         foreach ($linkRaw as $id => $obj) {
             $id = (int) $id;
-            if ($id <= 0 || !\is_object($obj)) {
-                continue;
-            }
+            if ($id <= 0 || !\is_object($obj)) { continue; }
             $e = $this->objectEntity($obj);
 
             $cid = (int) ($e->category_id ?? 0);
-            if (!isset($cats[$cid])) {
-                $cid = $uncatKey;
-            }
+            if (!isset($cats[$cid])) { $cid = $uncatKey; }
 
             $cats[$cid]['items'][] = [
-                'id' => $id,
-                'type' => 'link',
-                'label' => $this->resolveItemLabel('link', $e, $id),
-                'extra' => $this->buildExtra('link', $e) ?: new stdClass(),
+                'id'         => $id,
+                'type'       => 'link',
+                'label'      => $this->resolveItemLabel('link', $e, $id),
+                'extra'      => $this->buildExtra('link', $e) ?: new \stdClass(),
                 'selectable' => true,
                 'item_count' => 0,
             ];
@@ -2602,10 +3085,7 @@ private function buildLinkTreeForVue(object $course, string $groupTitle): array
 
         // Drop empty virtual category, sort, and finalize UI hints
         $catNodes = array_values(array_filter($cats, static function ($c) {
-            if (!empty($c['_virtual']) && empty($c['items'])) {
-                return false;
-            }
-
+            if (!empty($c['_virtual']) && empty($c['items'])) { return false; }
             return true;
         }));
 
@@ -2614,7 +3094,7 @@ private function buildLinkTreeForVue(object $course, string $groupTitle): array
                 usort($c['items'], static fn ($a, $b) => strcasecmp((string) $a['label'], (string) $b['label']));
             }
             $c['has_children'] = !empty($c['items']);
-            $c['item_count'] = \count($c['items'] ?? []);
+            $c['item_count']   = \count($c['items'] ?? []);
         }
         unset($c);
 
@@ -2623,7 +3103,7 @@ private function buildLinkTreeForVue(object $course, string $groupTitle): array
         $this->logDebug('[buildLinkTreeForVue] end', ['categories' => \count($catNodes)]);
 
         return [
-            'type' => 'link',
+            'type'  => 'link',
             'title' => $groupTitle,
             'items' => $catNodes,
         ];
@@ -2695,69 +3175,117 @@ private function filterCourseResources(object $course, array $selected): void
     }
 
     /**
-     * Returns the absolute path of the backupId in the backup directory.
+     * Resolve absolute path of a backupId inside the backups directory, with safety checks.
      */
     private function resolveBackupPath(string $backupId): string
     {
-        $backupDir = rtrim(CourseArchiver::getBackupDir(), '/');
+        $base = rtrim((string) CourseArchiver::getBackupDir(), DIRECTORY_SEPARATOR);
+        $baseReal = realpath($base) ?: $base;
 
-        return $backupDir.'/'.$backupId;
-    }
+        $file = basename($backupId);
+        $path = $baseReal . DIRECTORY_SEPARATOR . $file;
 
-    /**
-     * Heuristic: Does it look like a Moodle package?
-     * - If the extension (.mbz, .tgz, .gz) is used, we treat it as Moodle.
-     * - If it's a .zip file but CourseArchiver fails or contains "moodle_backup.xml," it's also Moodle.
-     */
-    private function isLikelyMoodlePackage(string $path, ?Throwable $priorError = null): bool
-    {
-        $ext = strtolower(pathinfo($path, PATHINFO_EXTENSION));
-        if (\in_array($ext, ['mbz', 'tgz', 'gz'], true)) {
-            return true;
-        }
-        if ('zip' === $ext && $priorError) {
-            return true;
+        $real = realpath($path);
+
+        if ($real !== false && strncmp($real, $baseReal, strlen($baseReal)) === 0) {
+            return $real;
         }
 
-        return false;
+        return $path;
     }
 
     /**
-     * Load a legacy course from a Chamilo or Moodle backup, testing both readers.
-     * - First try CourseArchiver (Chamilo).
-     * - If that fails, retry MoodleImport.
+     * Load a legacy Course object from any backup:
+     * - Chamilo (.zip with course_info.dat) → CourseArchiver::readCourse() or lenient fallback (your original logic)
+     * - Moodle (.mbz/.tgz/.gz or ZIP with moodle_backup.xml) → MoodleImport builder
+     *
+     * IMPORTANT:
+     * - Keeps your original Chamilo flow intact (strict → fallback manual decode/unserialize).
+     * - Tries Moodle only when the package looks like Moodle.
+     * - Adds __meta.import_source = "chamilo" | "moodle" for downstream logic.
      */
-    private function loadLegacyCourseForAnyBackup(string $backupId): object
+    private function loadLegacyCourseForAnyBackup(string $backupId, string $force = 'auto'): object
     {
         $path = $this->resolveBackupPath($backupId);
-        $this->logDebug('[loadLegacyCourseForAnyBackup] try Chamilo first', ['path' => $path]);
 
-        // Chamilo ZIP (course_info.dat)
-        try {
-            $course = CourseArchiver::readCourse($backupId, false);
-            if (!\is_object($course) || empty($course->resources) || !\is_array($course->resources)) {
-                throw new RuntimeException('Invalid Chamilo backup structure (empty resources)');
+        $force = strtolower($force);
+        if ('dat' === $force || 'chamilo' === $force) {
+            $looksMoodle = false;
+            $preferChamilo = true;
+        } elseif ('moodle' === $force) {
+            $looksMoodle = true;
+            $preferChamilo = false;
+        } else {
+            $looksMoodle   = $this->isMoodleByExt($path) || $this->zipHasMoodleBackupXml($path);
+            $preferChamilo = $this->zipHasCourseInfoDat($path);
+        }
+
+        if ($preferChamilo || !$looksMoodle) {
+            CourseArchiver::setDebug($this->debug);
+
+            try {
+                $course = CourseArchiver::readCourse($backupId, false);
+                if (\is_object($course)) {
+                    // … (resto igual)
+                    if (!isset($course->resources) || !\is_array($course->resources)) { $course->resources = []; }
+                    $course->resources['__meta'] = (array) ($course->resources['__meta'] ?? []);
+                    $course->resources['__meta']['import_source'] = 'chamilo';
+                    return $course;
+                }
+            } catch (\Throwable $e) {
+                $this->logDebug('[loadLegacyCourseForAnyBackup] readCourse() failed', ['error' => $e->getMessage()]);
             }
 
-            return $course;
-        } catch (Throwable $e) {
-            $this->logDebug('[loadLegacyCourseForAnyBackup] Chamilo reader failed, will try Moodle', ['err' => $e->getMessage()]);
-            $ext = strtolower(pathinfo($path, PATHINFO_EXTENSION));
-            if (!\in_array($ext, ['mbz', 'zip', 'gz', 'tgz'], true)) {
-                throw $e;
+            $zipPath = $this->resolveBackupPath($backupId);
+            $ci = $this->readCourseInfoFromZip($zipPath);
+            if (empty($ci['ok'])) {
+                if ($looksMoodle) {
+                    $this->logDebug('[loadLegacyCourseForAnyBackup] no course_info.dat, trying MoodleImport as last resort');
+                    return $this->loadMoodleCourseOrFail($path);
+                }
+                throw new \RuntimeException('course_info.dat not found in backup');
             }
-        }
 
-        // Moodle (.mbz/.zip/.tgz)
-        $this->logDebug('[loadLegacyCourseForAnyBackup] using MoodleImport');
-        $importer = new MoodleImport(debug: $this->debug);
-        $course = $importer->buildLegacyCourseFromMoodleArchive($path);
+            $raw = (string) $ci['data'];
+            $payload = base64_decode($raw, true);
+            if ($payload === false) { $payload = $raw; }
 
-        if (!\is_object($course) || empty($course->resources) || !\is_array($course->resources)) {
-            throw new RuntimeException('Moodle backup contains no importable resources');
+            $payload = CourseArchiver::preprocessSerializedPayloadForTypedProps($payload);
+            CourseArchiver::ensureLegacyAliases();
+
+            set_error_handler(static function () {});
+            try {
+                if (class_exists(\UnserializeApi::class)) {
+                    $c = \UnserializeApi::unserialize('course', $payload);
+                } else {
+                    $c = @unserialize($payload, ['allowed_classes' => true]);
+                }
+            } finally {
+                restore_error_handler();
+            }
+
+            if (!\is_object($c ?? null)) {
+                if ($looksMoodle) {
+                    $this->logDebug('[loadLegacyCourseForAnyBackup] Chamilo fallback failed, trying MoodleImport');
+                    return $this->loadMoodleCourseOrFail($path);
+                }
+                throw new \RuntimeException('Could not unserialize course (fallback)');
+            }
+
+            if (!isset($c->resources) || !\is_array($c->resources)) { $c->resources = []; }
+            $c->resources['__meta'] = (array) ($c->resources['__meta'] ?? []);
+            $c->resources['__meta']['import_source'] = 'chamilo';
+
+            return $c;
         }
 
-        return $course;
+        // Moodle path
+        if ($looksMoodle) {
+            $this->logDebug('[loadLegacyCourseForAnyBackup] using MoodleImport');
+            return $this->loadMoodleCourseOrFail($path);
+        }
+
+        throw new \RuntimeException('Unsupported package: neither course_info.dat nor moodle_backup.xml found.');
     }
 
     private function normalizeBucketsForRestorer(object $course): void
@@ -2834,7 +3362,6 @@ private function buildCc13Preview(object $course): array
         foreach (['document', 'Document', \defined('RESOURCE_DOCUMENT') ? RESOURCE_DOCUMENT : ''] as $cand) {
             if ($cand && isset($res[$cand]) && \is_array($res[$cand]) && !empty($res[$cand])) {
                 $docKey = $cand;
-
                 break;
             }
         }
@@ -2855,13 +3382,13 @@ private function buildCc13Preview(object $course): array
             $rel = ltrim(preg_replace('~^/?document/?~', '', $rawPath), '/');
 
             $fileType = strtolower((string) ($e->file_type ?? $e->filetype ?? ''));
-            $isDir = ('folder' === $fileType) || ('/' === substr($rawPath, -1));
+            $isDir = ($fileType === 'folder') || (substr($rawPath, -1) === '/');
 
             $title = (string) ($e->title ?? $wrap->name ?? basename($rel));
             $ims['resources']['webcontent'][] = [
                 'id' => (int) $iid,
                 'cc_type' => 'webcontent',
-                'title' => '' !== $title ? $title : basename($rel),
+                'title' => $title !== '' ? $title : basename($rel),
                 'rel' => $rel,
                 'is_dir' => $isDir,
                 'would_be_manifest_entry' => !$isDir,
@@ -2886,8 +3413,8 @@ private function expandCc13SelectionFromCategories(object $course, array $normSe
     {
         $out = [
             'documents' => (array) ($normSel['documents'] ?? []),
-            'links' => (array) ($normSel['links'] ?? []),
-            'forums' => (array) ($normSel['forums'] ?? []),
+            'links'     => (array) ($normSel['links']     ?? []),
+            'forums'    => (array) ($normSel['forums']    ?? []),
         ];
 
         $res = \is_array($course->resources ?? null) ? $course->resources : [];
@@ -2895,35 +3422,244 @@ private function expandCc13SelectionFromCategories(object $course, array $normSe
         // Link categories → link IDs
         if (!empty($normSel['link_category']) && \is_array($res['link'] ?? $res['Link'] ?? null)) {
             $selCats = array_fill_keys(array_map('strval', array_keys($normSel['link_category'])), true);
-            $links = $res['link'] ?? $res['Link'];
+            $links   = $res['link'] ?? $res['Link'];
             foreach ($links as $lid => $wrap) {
-                if (!\is_object($wrap)) {
-                    continue;
-                }
+                if (!\is_object($wrap)) { continue; }
                 $e = (isset($wrap->obj) && \is_object($wrap->obj)) ? $wrap->obj : $wrap;
                 $cid = (string) (int) ($e->category_id ?? 0);
-                if (isset($selCats[$cid])) {
-                    $out['links'][(string) $lid] = true;
-                }
+                if (isset($selCats[$cid])) { $out['links'][(string)$lid] = true; }
             }
         }
 
         // Forum categories → forum IDs
         if (!empty($normSel['forum_category']) && \is_array($res['forum'] ?? $res['Forum'] ?? null)) {
             $selCats = array_fill_keys(array_map('strval', array_keys($normSel['forum_category'])), true);
-            $forums = $res['forum'] ?? $res['Forum'];
+            $forums  = $res['forum'] ?? $res['Forum'];
             foreach ($forums as $fid => $wrap) {
-                if (!\is_object($wrap)) {
-                    continue;
-                }
+                if (!\is_object($wrap)) { continue; }
                 $e = (isset($wrap->obj) && \is_object($wrap->obj)) ? $wrap->obj : $wrap;
                 $cid = (string) (int) ($e->forum_category ?? $e->forum_category_id ?? $e->category_id ?? 0);
-                if (isset($selCats[$cid])) {
-                    $out['forums'][(string) $fid] = true;
-                }
+                if (isset($selCats[$cid])) { $out['forums'][(string)$fid] = true; }
             }
         }
 
         return $out;
     }
+
+    /**
+     * Infer tool buckets required by a given selection payload (used in 'selected' scope).
+     *
+     * Expected selection items like: { "type": "document"|"quiz"|"survey"|... , "id": <int> }
+     *
+     * @param array<int,array<string,mixed>> $selected
+     * @return string[]
+     */
+    private function inferToolsFromSelection(array $selected): array
+    {
+        $has = static fn(string $k): bool =>
+            !empty($selected[$k]) && \is_array($selected[$k]) && \count($selected[$k]) > 0;
+
+        $want = [];
+
+        // documents
+        if ($has('document')) {
+            $want[] = 'documents';
+        }
+
+        // links (categories imply links too)
+        if ($has('link') || $has('link_category')) {
+            $want[] = 'links';
+        }
+
+        // forums (any of the family implies forums)
+        if ($has('forum') || $has('forum_category') || $has('forum_topic') || $has('thread') || $has('post') || $has('forum_post')) {
+            $want[] = 'forums';
+        }
+
+        // quizzes / questions
+        if ($has('quiz') || $has('exercise') || $has('exercise_question')) {
+            $want[] = 'quizzes';
+            $want[] = 'quiz_questions';
+        }
+
+        // surveys / questions / invitations
+        if ($has('survey') || $has('survey_question') || $has('survey_invitation')) {
+            $want[] = 'surveys';
+            $want[] = 'survey_questions';
+        }
+
+        // learnpaths
+        if ($has('learnpath') || $has('learnpath_category')) {
+            $want[] = 'learnpaths';
+            $want[] = 'learnpath_category';
+        }
+
+        // others
+        if ($has('work'))     { $want[] = 'works'; }
+        if ($has('glossary')) { $want[] = 'glossary'; }
+        if ($has('tool_intro')) { $want[] = 'tool_intro'; }
+
+        // Dedup
+        return array_values(array_unique(array_filter($want)));
+    }
+
+    private function intersectBucketByIds(array $bucket, array $idsMap): array
+    {
+        $out = [];
+        foreach ($bucket as $id => $obj) {
+            $ent = (isset($obj->obj) && \is_object($obj->obj)) ? $obj->obj : $obj;
+            $k1  = (string) $id;
+            $k2  = (string) ($ent->source_id ?? $obj->source_id ?? '');
+            if (isset($idsMap[$k1]) || ($k2 !== '' && isset($idsMap[$k2]))) {
+                $out[$id] = $obj;
+            }
+        }
+        return $out;
+    }
+
+    private function bucketKeyCandidates(string $type): array
+    {
+        $t = $this->normalizeTypeKey($type);
+
+        // Constants (string values) if defined
+        $RD  = \defined('RESOURCE_DOCUMENT')       ? (string) RESOURCE_DOCUMENT       : '';
+        $RL  = \defined('RESOURCE_LINK')           ? (string) RESOURCE_LINK           : '';
+        $RF  = \defined('RESOURCE_FORUM')          ? (string) RESOURCE_FORUM          : '';
+        $RFT = \defined('RESOURCE_FORUMTOPIC')     ? (string) RESOURCE_FORUMTOPIC     : '';
+        $RFP = \defined('RESOURCE_FORUMPOST')      ? (string) RESOURCE_FORUMPOST      : '';
+        $RQ  = \defined('RESOURCE_QUIZ')           ? (string) RESOURCE_QUIZ           : '';
+        $RQQ = \defined('RESOURCE_QUIZQUESTION')   ? (string) RESOURCE_QUIZQUESTION   : '';
+        $RS  = \defined('RESOURCE_SURVEY')         ? (string) RESOURCE_SURVEY         : '';
+        $RSQ = \defined('RESOURCE_SURVEYQUESTION') ? (string) RESOURCE_SURVEYQUESTION : '';
+
+        $map = [
+            'document'         => ['document', 'Document', $RD],
+            'link'             => ['link', 'Link', $RL],
+            'link_category'    => ['link_category', 'Link_Category'],
+            'forum'            => ['forum', 'Forum', $RF],
+            'forum_category'   => ['forum_category', 'Forum_Category'],
+            'forum_topic'      => ['forum_topic', 'thread', $RFT],
+            'forum_post'       => ['forum_post', 'post', $RFP],
+            'quiz'             => ['quiz', 'Quiz', $RQ],
+            'exercise_question'=> ['Exercise_Question', 'exercise_question', $RQQ],
+            'survey'           => ['survey', 'Survey', $RS],
+            'survey_question'  => ['Survey_Question', 'survey_question', $RSQ],
+            'tool_intro'       => ['tool_intro', 'Tool introduction'],
+        ];
+
+        $c = $map[$t] ?? [$t, ucfirst($t)];
+        return array_values(array_filter($c, static fn($x) => $x !== ''));
+    }
+
+    private function findBucketKey(array $res, string $type): ?string
+    {
+        $key = $this->firstExistingKey($res, $this->bucketKeyCandidates($type));
+        return $key !== null ? (string) $key : null;
+    }
+
+    private function findBucket(array $res, string $type): array
+    {
+        $k = $this->findBucketKey($res, $type);
+        return ($k !== null && isset($res[$k]) && \is_array($res[$k])) ? $res[$k] : [];
+    }
+
+    /** True if file extension suggests a Moodle backup. */
+    private function isMoodleByExt(string $path): bool
+    {
+        $ext = strtolower(pathinfo($path, PATHINFO_EXTENSION));
+        return in_array($ext, ['mbz','tgz','gz'], true);
+    }
+
+    /** Quick ZIP probe for 'moodle_backup.xml'. Safe no-op for non-zip files. */
+    private function zipHasMoodleBackupXml(string $path): bool
+    {
+        $ext = strtolower(pathinfo($path, PATHINFO_EXTENSION));
+        // Many .mbz are plain ZIPs; try to open if extension is zip/mbz
+        if (!in_array($ext, ['zip','mbz'], true)) {
+            return false;
+        }
+        $zip = new \ZipArchive();
+        if (true !== ($err = $zip->open($path))) {
+            return false;
+        }
+        $idx = $zip->locateName('moodle_backup.xml', \ZipArchive::FL_NOCASE);
+        $zip->close();
+        return ($idx !== false);
+    }
+
+    /** Quick ZIP probe for 'course_info.dat'. Safe no-op for non-zip files. */
+    private function zipHasCourseInfoDat(string $path): bool
+    {
+        $ext = strtolower(pathinfo($path, PATHINFO_EXTENSION));
+        if (!in_array($ext, ['zip','mbz'], true)) {
+            return false;
+        }
+        $zip = new \ZipArchive();
+        if (true !== ($err = $zip->open($path))) {
+            return false;
+        }
+        // common locations
+        foreach (['course_info.dat','course/course_info.dat','backup/course_info.dat'] as $cand) {
+            $idx = $zip->locateName($cand, \ZipArchive::FL_NOCASE);
+            if ($idx !== false) { $zip->close(); return true; }
+        }
+        $zip->close();
+        return false;
+    }
+
+    /**
+     * Build legacy Course graph from a Moodle archive and set __meta.import_source.
+     * Throws RuntimeException on failure.
+     */
+    private function loadMoodleCourseOrFail(string $absPath): object
+    {
+        if (!class_exists(MoodleImport::class)) {
+            throw new \RuntimeException('MoodleImport class not available');
+        }
+        $importer = new MoodleImport(debug: $this->debug);
+
+        if (!method_exists($importer, 'buildLegacyCourseFromMoodleArchive')) {
+            throw new \RuntimeException('MoodleImport::buildLegacyCourseFromMoodleArchive() not available');
+        }
+
+        $course = $importer->buildLegacyCourseFromMoodleArchive($absPath);
+
+        if (!\is_object($course) || empty($course->resources) || !\is_array($course->resources)) {
+            throw new \RuntimeException('Moodle backup contains no importable resources');
+        }
+
+        $course->resources['__meta'] = (array) ($course->resources['__meta'] ?? []);
+        $course->resources['__meta']['import_source'] = 'moodle';
+
+        return $course;
+    }
+
+    /**
+     * Recursively sanitize an unserialized PHP graph:
+     * - Objects are cast to arrays, keys like "\0Class\0prop" become "prop"
+     * - Returns arrays/stdClass with only public-like keys
+     */
+    private function sanitizePhpGraph(mixed $value): mixed
+    {
+        if (\is_array($value)) {
+            $out = [];
+            foreach ($value as $k => $v) {
+                $ck = \is_string($k) ? (string) preg_replace('/^\0.*\0/', '', $k) : $k;
+                $out[$ck] = $this->sanitizePhpGraph($v);
+            }
+            return $out;
+        }
+
+        if (\is_object($value)) {
+            $arr = (array) $value;
+            $clean = [];
+            foreach ($arr as $k => $v) {
+                $ck = \is_string($k) ? (string) preg_replace('/^\0.*\0/', '', $k) : $k;
+                $clean[$ck] = $this->sanitizePhpGraph($v);
+            }
+            return (object) $clean;
+        }
+
+        return $value;
+    }
 }
diff --git a/src/CourseBundle/Component/CourseCopy/CourseArchiver.php b/src/CourseBundle/Component/CourseCopy/CourseArchiver.php
index 9da7d535d7d..bbdae1729ce 100644
--- a/src/CourseBundle/Component/CourseCopy/CourseArchiver.php
+++ b/src/CourseBundle/Component/CourseCopy/CourseArchiver.php
@@ -14,6 +14,7 @@
 use RecursiveIteratorIterator;
 use RuntimeException;
 use Symfony\Component\Filesystem\Filesystem;
+use Throwable;
 use UnserializeApi;
 use ZipArchive;
 
@@ -23,59 +24,98 @@
  * Some functions to write a course-object to a zip-file and to read a course-
  * object from such a zip-file.
  *
- * @author Bart Mollet <bart.mollet@hogent.be>
+ * Hardened to support PHP 8+ typed properties and legacy backups.
  *
- * @todo Use archive-folder of Chamilo?
+ * @author Bart Mollet
  */
 class CourseArchiver
 {
-    /**
-     * @return string
-     */
+    /** @var bool Global debug flag (true by default) */
+    private static bool $debug = true;
+
+    /** Debug logger (safe JSON, truncated) */
+    private static function dlog(string $stage, mixed $payload = null): void
+    {
+        if (!self::$debug) { return; }
+        $prefix = 'COURSE_ARCHIVER';
+        if ($payload === null) {
+            error_log("$prefix: $stage");
+            return;
+        }
+        try {
+            $json = json_encode($payload, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
+            if ($json !== null && strlen($json) > 8000) {
+                $json = substr($json, 0, 8000) . '…(truncated)';
+            }
+        } catch (Throwable $e) {
+            $json = '[payload_json_error: ' . $e->getMessage() . ']';
+        }
+        error_log("$prefix: $stage -> " . $json);
+    }
+
+    /** Allow toggling debug at runtime. */
+    public static function setDebug(?bool $flag): void
+    {
+        if ($flag === null) { return; }
+        self::$debug = (bool) $flag;
+    }
+
+    /** Expose aliases/typed-props helpers to other components. */
+    public static function preprocessSerializedPayloadForTypedProps(string $serialized): string
+    {
+        return self::coerceNumericStringsInSerialized($serialized);
+    }
+    public static function ensureLegacyAliases(): void
+    {
+        self::registerLegacyAliases();
+    }
+
+    /** @return string */
     public static function getBackupDir()
     {
-        return api_get_path(SYS_ARCHIVE_PATH).'course_backups/';
+        return api_get_path(SYS_ARCHIVE_PATH) . 'course_backups/';
     }
 
-    /**
-     * @return string
-     */
+    /** @return string */
     public static function createBackupDir()
     {
         $perms = api_get_permissions_for_new_directories();
         $dir = self::getBackupDir();
         $fs = new Filesystem();
         $fs->mkdir($dir, $perms);
+        self::dlog('createBackupDir', ['dir' => $dir, 'perms' => $perms]);
 
         return $dir;
     }
 
-    /**
-     * Delete old temp-dirs.
-     */
+    /** Delete old temp-dirs. */
     public static function cleanBackupDir(): void
     {
         $dir = self::getBackupDir();
+        self::dlog('cleanBackupDir.begin', ['dir' => $dir]);
+
         if (is_dir($dir)) {
             if ($handle = @opendir($dir)) {
                 while (false !== ($file = readdir($handle))) {
-                    if ('.' != $file && '..' != $file
-                          && str_starts_with($file, 'CourseArchiver_')
-                        && is_dir($dir.'/'.$file)
+                    if ($file !== '.' && $file !== '..'
+                        && str_starts_with($file, 'CourseArchiver_')
+                        && is_dir($dir . '/' . $file)
                     ) {
-                        rmdirr($dir.'/'.$file);
+                        @rmdirr($dir . '/' . $file);
+                        self::dlog('cleanBackupDir.removed', ['path' => $dir . '/' . $file]);
                     }
                 }
                 closedir($handle);
             }
         }
+
+        self::dlog('cleanBackupDir.end');
     }
 
     /**
      * Write a course and all its resources to a zip-file.
      *
      * @param mixed $course
-     *
      * @return string A pointer to the zip-file
      */
     public static function createBackup($course)
@@ -87,124 +127,134 @@ public static function createBackup($course)
         $backupDirectory = self::getBackupDir();
 
         // Create a temp directory
-        $backup_dir = $backupDirectory.'CourseArchiver_'.api_get_unique_id().'/';
+        $backup_dir = $backupDirectory . 'CourseArchiver_' . api_get_unique_id() . '/';
 
         // All course-information will be stored in course_info.dat
-        $course_info_file = $backup_dir.'course_info.dat';
+        $course_info_file = $backup_dir . 'course_info.dat';
 
         $user = api_get_user_info();
         $date = new DateTime(api_get_local_time());
-        $zipFileName = $user['user_id'].'_'.$course->code.'_'.$date->format('Ymd-His').'.zip';
-        $zipFilePath = $backupDirectory.$zipFileName;
+        $zipFileName = $user['user_id'] . '_' . $course->code . '_' . $date->format('Ymd-His') . '.zip';
+        $zipFilePath = $backupDirectory . $zipFileName;
+
+        self::dlog('createBackup.begin', [
+            'zip' => $zipFileName,
+            'backup_dir' => $backup_dir,
+            'course_code' => $course->code ?? null,
+        ]);
 
         $php_errormsg = '';
         $res = @mkdir($backup_dir, $perm_dirs);
-        if (false === $res) {
-            // TODO set and handle an error message telling the user to review the permissions on the archive directory
-            error_log(__FILE__.' line '.__LINE__.': '.(false != \ini_get('track_errors') ? $php_errormsg : 'error not recorded because track_errors is off in your php.ini').' - This error, occuring because your archive directory will not let this script write data into it, will prevent courses backups to be created', 0);
+        if ($res === false) {
+            error_log(__FILE__ . ' line ' . __LINE__ . ': ' . ($php_errormsg ?: 'mkdir failed') . ' - Archive directory not writable; will prevent backups.', 0);
         }
+
         // Write the course-object to the file
         $fp = @fopen($course_info_file, 'w');
-        if (false === $fp) {
-            error_log(__FILE__.' line '.__LINE__.': '.(false != \ini_get('track_errors') ? $php_errormsg : 'error not recorded because track_errors is off in your php.ini'), 0);
+        if ($fp === false) {
+            error_log(__FILE__ . ' line ' . __LINE__ . ': ' . ($php_errormsg ?: 'fopen failed for course_info.dat'), 0);
         }
 
-        $res = @fwrite($fp, base64_encode(serialize($course)));
-        if (false === $res) {
-            error_log(__FILE__.' line '.__LINE__.': '.(false != \ini_get('track_errors') ? $php_errormsg : 'error not recorded because track_errors is off in your php.ini'), 0);
+        $serialized = @serialize($course);
+        $b64 = base64_encode($serialized);
+        $okWrite = $fp !== false ? @fwrite($fp, $b64) : false;
+        if ($okWrite === false) {
+            error_log(__FILE__ . ' line ' . __LINE__ . ': ' . ($php_errormsg ?: 'fwrite failed for course_info.dat'), 0);
         }
-
-        $res = @fclose($fp);
-        if (false === $res) {
-            error_log(__FILE__.' line '.__LINE__.': '.(false != \ini_get('track_errors') ? $php_errormsg : 'error not recorded because track_errors is off in your php.ini'), 0);
+        if ($fp !== false) {
+            @fclose($fp);
         }
 
+        self::dlog('createBackup.course_info', [
+            'size_bytes' => @filesize($course_info_file),
+            'md5' => @md5_file($course_info_file),
+        ]);
+
         // Copy all documents to the temp-dir
-        if (isset($course->resources[RESOURCE_DOCUMENT]) && \is_array($course->resources[RESOURCE_DOCUMENT])) {
-            $webEditorCss = api_get_path(WEB_CSS_PATH).'editor.css';
+        if (isset($course->resources[RESOURCE_DOCUMENT]) && is_array($course->resources[RESOURCE_DOCUMENT])) {
+            $webEditorCss = api_get_path(WEB_CSS_PATH) . 'editor.css';
 
             /** @var Document $document */
             foreach ($course->resources[RESOURCE_DOCUMENT] as $document) {
                 if ('document' === $document->file_type) {
-                    $doc_dir = $backup_dir.$document->path;
-                    @mkdir(\dirname($doc_dir), $perm_dirs, true);
-                    if (file_exists($course->path.$document->path)) {
-                        copy($course->path.$document->path, $doc_dir);
+                    $doc_dir = $backup_dir . $document->path;
+                    @mkdir(dirname($doc_dir), $perm_dirs, true);
+                    if (file_exists($course->path . $document->path)) {
+                        @copy($course->path . $document->path, $doc_dir);
                         // Check if is html or htm
                         $extension = pathinfo(basename($document->path), PATHINFO_EXTENSION);
-
                         switch ($extension) {
                             case 'html':
                             case 'htm':
-                                $contents = file_get_contents($doc_dir);
-                                $contents = str_replace(
-                                    $webEditorCss,
-                                    '{{css_editor}}',
-                                    $contents
-                                );
-                                file_put_contents($doc_dir, $contents);
-
+                                $contents = @file_get_contents($doc_dir);
+                                if ($contents !== false) {
+                                    $contents = str_replace(
+                                        $webEditorCss,
+                                        '{{css_editor}}',
+                                        $contents
+                                    );
+                                    @file_put_contents($doc_dir, $contents);
+                                }
                                 break;
                         }
                     }
                 } else {
-                    @mkdir($backup_dir.$document->path, $perm_dirs, true);
+                    @mkdir($backup_dir . $document->path, $perm_dirs, true);
                 }
             }
         }
 
         // Copy all scorm documents to the temp-dir
-        if (isset($course->resources[RESOURCE_SCORM]) && \is_array($course->resources[RESOURCE_SCORM])) {
+        if (isset($course->resources[RESOURCE_SCORM]) && is_array($course->resources[RESOURCE_SCORM])) {
             foreach ($course->resources[RESOURCE_SCORM] as $document) {
-                copyDirTo($course->path.$document->path, $backup_dir.$document->path, false);
+                @copyDirTo($course->path . $document->path, $backup_dir . $document->path, false);
             }
         }
 
         // Copy calendar attachments.
-        if (isset($course->resources[RESOURCE_EVENT]) && \is_array($course->resources[RESOURCE_EVENT])) {
-            $doc_dir = \dirname($backup_dir.'/upload/calendar/');
+        if (isset($course->resources[RESOURCE_EVENT]) && is_array($course->resources[RESOURCE_EVENT])) {
+            $doc_dir = dirname($backup_dir . '/upload/calendar/');
             @mkdir($doc_dir, $perm_dirs, true);
-            copyDirTo($course->path.'upload/calendar/', $doc_dir, false);
+            @copyDirTo($course->path . 'upload/calendar/', $doc_dir, false);
         }
 
         // Copy Learning path author image.
-        if (isset($course->resources[RESOURCE_LEARNPATH]) && \is_array($course->resources[RESOURCE_LEARNPATH])) {
-            $doc_dir = \dirname($backup_dir.'/upload/learning_path/');
+        if (isset($course->resources[RESOURCE_LEARNPATH]) && is_array($course->resources[RESOURCE_LEARNPATH])) {
+            $doc_dir = dirname($backup_dir . '/upload/learning_path/');
             @mkdir($doc_dir, $perm_dirs, true);
-            copyDirTo($course->path.'upload/learning_path/', $doc_dir, false);
+            @copyDirTo($course->path . 'upload/learning_path/', $doc_dir, false);
         }
 
         // Copy announcements attachments.
-        if (isset($course->resources[RESOURCE_ANNOUNCEMENT]) && \is_array($course->resources[RESOURCE_ANNOUNCEMENT])) {
-            $doc_dir = \dirname($backup_dir.'/upload/announcements/');
+        if (isset($course->resources[RESOURCE_ANNOUNCEMENT]) && is_array($course->resources[RESOURCE_ANNOUNCEMENT])) {
+            $doc_dir = dirname($backup_dir . '/upload/announcements/');
             @mkdir($doc_dir, $perm_dirs, true);
-            copyDirTo($course->path.'upload/announcements/', $doc_dir, false);
+            @copyDirTo($course->path . 'upload/announcements/', $doc_dir, false);
         }
 
         // Copy work folders (only folders)
-        if (isset($course->resources[RESOURCE_WORK]) && \is_array($course->resources[RESOURCE_WORK])) {
-            $doc_dir = $backup_dir.'work';
+        if (isset($course->resources[RESOURCE_WORK]) && is_array($course->resources[RESOURCE_WORK])) {
+            $doc_dir = $backup_dir . 'work';
             @mkdir($doc_dir, $perm_dirs, true);
-            copyDirWithoutFilesTo($course->path.'work/', $doc_dir);
+            @copyDirWithoutFilesTo($course->path . 'work/', $doc_dir);
         }
 
-        if (isset($course->resources[RESOURCE_ASSET]) && \is_array($course->resources[RESOURCE_ASSET])) {
+        if (isset($course->resources[RESOURCE_ASSET]) && is_array($course->resources[RESOURCE_ASSET])) {
             /** @var Asset $asset */
             foreach ($course->resources[RESOURCE_ASSET] as $asset) {
-                $doc_dir = $backup_dir.$asset->path;
-                @mkdir(\dirname($doc_dir), $perm_dirs, true);
-                $assetPath = $course->path.$asset->path;
+                $doc_dir = $backup_dir . $asset->path;
+                @mkdir(dirname($doc_dir), $perm_dirs, true);
+                $assetPath = $course->path . $asset->path;
 
                 if (!file_exists($assetPath)) {
                     continue;
                 }
 
-                if (is_dir($course->path.$asset->path)) {
-                    copyDirTo($course->path.$asset->path, $doc_dir, false);
-
-                    continue;
+                if (is_dir($assetPath)) {
+                    @copyDirTo($assetPath, $doc_dir, false);
+                } else {
+                    @copy($assetPath, $doc_dir);
                 }
-                copy($course->path.$asset->path, $doc_dir);
             }
         }
 
@@ -213,14 +263,15 @@ public static function createBackup($course)
         $zip->create($backup_dir, PCLZIP_OPT_REMOVE_PATH, $backup_dir);
 
         // Remove the temp-dir.
-        rmdirr($backup_dir);
+        @rmdirr($backup_dir);
+
+        self::dlog('createBackup.end', ['zip' => $zipFileName, 'path' => $zipFilePath]);
 
         return $zipFileName;
     }
 
     /**
      * @param int $user_id
-     *
      * @return array
      */
     public static function getAvailableBackups($user_id = null)
@@ -235,17 +286,17 @@ public static function getAvailableBackups($user_id = null)
         if ($dir = opendir($dirname)) {
             while (false !== ($file = readdir($dir))) {
                 $file_parts = explode('_', $file);
-                if (3 == \count($file_parts)) {
+                if (3 == count($file_parts)) {
                     $owner_id = $file_parts[0];
                     $course_code = $file_parts[1];
                     $file_parts = explode('.', $file_parts[2]);
                     $date = $file_parts[0];
-                    $ext = isset($file_parts[1]) ? $file_parts[1] : null;
-                    if ('zip' == $ext && (null != $user_id && $owner_id == $user_id || null == $user_id)) {
+                    $ext = $file_parts[1] ?? null;
+                    if ('zip' == $ext && ((null != $user_id && $owner_id == $user_id) || (null == $user_id))) {
                         $date =
-                            substr($date, 0, 4).'-'.substr($date, 4, 2).'-'.
-                            substr($date, 6, 2).' '.substr($date, 9, 2).':'.
-                            substr($date, 11, 2).':'.substr($date, 13, 2);
+                            substr($date, 0, 4) . '-' . substr($date, 4, 2) . '-' .
+                            substr($date, 6, 2) . ' ' . substr($date, 9, 2) . ':' .
+                            substr($date, 11, 2) . ':' . substr($date, 13, 2);
                         $backup_files[] = [
                             'file' => $file,
                             'date' => $date,
@@ -261,71 +312,86 @@ public static function getAvailableBackups($user_id = null)
     }
 
     /**
-     * @param array $file
-     *
+     * @param array|string $file path or $_FILES['tmp_name']
      * @return bool|string
      */
     public static function importUploadedFile($file)
     {
-        $new_filename = uniqid('import_file', true).'.zip';
+        $new_filename = uniqid('import_file', true) . '.zip';
         $new_dir = self::getBackupDir();
         if (!is_dir($new_dir)) {
             $fs = new Filesystem();
             $fs->mkdir($new_dir);
         }
         if (is_dir($new_dir) && is_writable($new_dir)) {
-            move_uploaded_file($file, $new_dir.$new_filename);
+            // move_uploaded_file() may fail in CLI/tests; try rename() as fallback
+            $src = is_array($file) ? ($file['tmp_name'] ?? '') : (string) $file;
+            $dst = $new_dir . $new_filename;
 
-            return $new_filename;
+            $moved = @move_uploaded_file($src, $dst);
+            if (!$moved) {
+                $moved = @rename($src, $dst);
+            }
+            if ($moved) {
+                self::dlog('importUploadedFile.ok', ['dst' => $dst, 'size' => @filesize($dst)]);
+                return $new_filename;
+            }
+
+            self::dlog('importUploadedFile.fail', ['src' => $src, 'dst' => $dst]);
+            return false;
         }
 
+        self::dlog('importUploadedFile.dir_not_writable', ['dir' => $new_dir]);
         return false;
     }
 
     /**
      * Read a legacy course backup (.zip) and return a Course object.
      * - Extracts the zip into a temp dir.
-     * - Finds and decodes course_info.dat (base64 + serialize).
+     * - Finds and decodes course_info.dat:
+     *     prefers base64(serialize), then raw serialize as fallback.
      * - Registers legacy aliases/stubs BEFORE unserialize (critical).
-     * - Normalizes common identifier fields to int after unserialize.
+     * - Coerces typed-prop numeric strings BEFORE unserialize.
+     * - Tries relaxed unserialize (no class instantiation) on failure and converts incomplete classes to stdClass.
+     * - Normalizes common numeric identifiers AFTER unserialize (safe).
+     *
+     * @throws RuntimeException
      */
     public static function readCourse(string $filename, bool $delete = false): false|Course
     {
-        // Clean temp backup dirs and ensure backup dir exists
         self::cleanBackupDir();
         self::createBackupDir();
 
-        $backupDir = rtrim(self::getBackupDir(), '/').'/';
-        $zipPath = $backupDir.$filename;
+        $backupDir = rtrim(self::getBackupDir(), '/') . '/';
+        $zipPath = $backupDir . $filename;
 
         if (!is_file($zipPath)) {
-            throw new RuntimeException('Backup file not found: '.$filename);
+            throw new RuntimeException('Backup file not found: ' . $filename);
         }
 
+        self::dlog('readCourse.begin', ['filename' => $filename, 'zipPath' => $zipPath]);
+
         // 1) Extract zip into a temp directory
-        $tmp = $backupDir.'CourseArchiver_'.uniqid('', true).'/';
+        $tmp = $backupDir . 'CourseArchiver_' . uniqid('', true) . '/';
         (new Filesystem())->mkdir($tmp);
 
         $zip = new ZipArchive();
         if (true !== $zip->open($zipPath)) {
-            throw new RuntimeException('Cannot open zip: '.$filename);
+            throw new RuntimeException('Cannot open zip: ' . $filename);
         }
         if (!$zip->extractTo($tmp)) {
             $zip->close();
-
-            throw new RuntimeException('Cannot extract zip: '.$filename);
+            throw new RuntimeException('Cannot extract zip: ' . $filename);
         }
         $zip->close();
 
-        // 2) Read and decode course_info.dat (base64 + serialize)
-        $courseInfoDat = $tmp.'course_info.dat';
+        // 2) Read course_info.dat (search nested if necessary)
+        $courseInfoDat = $tmp . 'course_info.dat';
         if (!is_file($courseInfoDat)) {
-            // Fallback: search nested locations
             $rii = new RecursiveIteratorIterator(new RecursiveDirectoryIterator($tmp));
             foreach ($rii as $f) {
-                if ($f->isFile() && 'course_info.dat' === $f->getFilename()) {
+                if ($f->isFile() && $f->getFilename() === 'course_info.dat') {
                     $courseInfoDat = $f->getPathname();
-
                     break;
                 }
             }
@@ -334,42 +400,117 @@ public static function readCourse(string $filename, bool $delete = false): false
             }
         }
 
-        $raw = file_get_contents($courseInfoDat);
+        $raw = (string) @file_get_contents($courseInfoDat);
+        if ($raw === '') {
+            throw new RuntimeException('course_info.dat is empty');
+        }
+
+        self::dlog('readCourse.course_info', [
+            'path' => $courseInfoDat,
+            'size' => strlen($raw),
+            'md5'  => md5($raw),
+            'magic_ascii' => preg_replace('/[^\x20-\x7E]/', '.', substr($raw, 0, 16)),
+            'magic_hex'   => bin2hex(substr($raw, 0, 8)),
+        ]);
+
+        // 3) Decode: prefer base64(serialize), else raw serialize
         $payload = base64_decode($raw, true);
-        if (false === $payload) {
-            throw new RuntimeException('course_info.dat is not valid base64');
+        $encoding = 'base64(php-serialize)';
+
+        if ($payload === false) {
+            // Some very old backups stored raw serialize without base64
+            $payload = $raw;
+            $encoding = 'php-serialize';
         }
 
-        // 3) Coerce numeric-string identifiers to integers *before* unserialize
-        //    This prevents "Cannot assign string to property ... of type int"
-        //    on typed properties (handles public/protected/private names).
+        // 4) Coerce numeric-string identifiers to int in serialized payload
         $payload = self::coerceNumericStringsInSerialized($payload);
 
-        // 4) Register legacy aliases BEFORE unserialize (critical for v1 backups)
+        // 5) Register legacy aliases BEFORE unserialize
         self::registerLegacyAliases();
 
-        // 5) Unserialize using UnserializeApi if present (v1-compatible)
-        if (class_exists('UnserializeApi')) {
-            /** @var Course $course */
-            $course = UnserializeApi::unserialize('course', $payload);
-        } else {
-            /** @var Course|false $course */
-            $course = @unserialize($payload, ['allowed_classes' => true]);
+        // 6) Unserialize with robust fallbacks
+        $course = null;
+        $unserOk = false;
+        $unserErr = null;
+        $usedRelaxed = false;
+
+        set_error_handler(static function () { /* suppress E_NOTICE/E_WARNING from unserialize */ });
+        try {
+            if (class_exists('UnserializeApi')) {
+                /** @var Course $c */
+                $c = UnserializeApi::unserialize('course', $payload);
+                $course = $c;
+                $unserOk = is_object($course);
+            } else {
+                /** @var Course|false $c */
+                $c = @unserialize($payload, ['allowed_classes' => true]); // may throw TypeError with typed props
+                if (is_object($c) || ($c === false && trim($payload) === 'b:0;')) {
+                    $course = $c;
+                    $unserOk = is_object($course);
+                } else {
+                    $unserOk = false;
+                }
+
+                // Relaxed fallback: do not instantiate classes; convert incomplete classes to stdClass
+                if (!$unserOk) {
+                    /** @var mixed $c2 */
+                    $c2 = @unserialize($payload, ['allowed_classes' => false]);
+                    if ($c2 !== false || trim($payload) === 'b:0;') {
+                        $c2 = self::deincomplete($c2);
+                        if (is_object($c2)) {
+                            $course = $c2;
+                            $unserOk = true;
+                            $usedRelaxed = true;
+                        }
+                    }
+                }
+            }
+        } catch (Throwable $e) {
+            $unserErr = $e->getMessage();
+
+            // Hard fallback inside catch as well
+            try {
+                $c2 = @unserialize($payload, ['allowed_classes' => false]);
+                if ($c2 !== false || trim($payload) === 'b:0;') {
+                    $c2 = self::deincomplete($c2);
+                    if (is_object($c2)) {
+                        $course = $c2;
+                        $unserOk = true;
+                        $usedRelaxed = true;
+                        $unserErr = null;
+                    }
+                }
+            } catch (Throwable $e2) {
+                $unserErr = $unserErr . ' | relaxed: ' . $e2->getMessage();
+            }
+        } finally {
+            restore_error_handler();
         }
 
-        if (!\is_object($course)) {
+        self::dlog('readCourse.unserialize', [
+            'ok' => $unserOk,
+            'encoding' => $encoding,
+            'relaxed' => $usedRelaxed,
+            'error' => $unserErr,
+        ]);
+
+        if (!$unserOk || !is_object($course)) {
             throw new RuntimeException('Could not unserialize legacy course');
         }
 
-        // 6) Normalize common numeric identifiers after unserialize (extra safety)
+        // 7) Normalize numeric identifiers post-unserialize (safe)
         self::normalizeIds($course);
 
-        // 7) Optionally delete uploaded file (compat with v1)
+        // 8) Optionally delete uploaded file (compat with v1)
         if ($delete && is_file($zipPath)) {
             @unlink($zipPath);
+            self::dlog('readCourse.deleted_zip', ['path' => $zipPath]);
         }
 
-        // Keep temp dir until restore phase if files are needed later (compat with v1)
+        self::dlog('readCourse.end', ['ok' => true]);
+
+        // Keep temp dir; some restore flows need extracted files
         return $course;
     }
 
@@ -382,79 +523,122 @@ public static function readCourse(string $filename, bool $delete = false): false
      */
     private static function coerceNumericStringsInSerialized(string $ser): string
     {
-        // Identifier keys that must be integers
+        // If it looks like JSON, do nothing (defensive)
+        $t = ltrim($ser);
+        if ($t !== '' && ($t[0] === '{' || $t[0] === '[')) {
+            self::dlog('coerceNumericStrings.skip_json');
+            return $ser;
+        }
+
+        // Common identifier keys (conservative list)
         $keys = [
-            'id', 'iid', 'c_id', 'parent_id', 'thematic_id', 'attendance_id',
-            'room_id', 'display_order', 'session_id', 'category_id',
+            'id','iid','c_id','parent_id','thematic_id','attendance_id',
+            'room_id','display_order','session_id','category_id',
+            // forum/link/doc/quiz/survey typical relations:
+            'forum_id','thread_id','post_id','survey_id','question_id',
+            'document_id','doc_id','link_id','quiz_id','work_id',
         ];
 
-        /**
-         * Build a pattern that matches any of these name encodings:
-         *  - public:   "id"
-         *  - protected:"\0*\0id"
-         *  - private:  "\0SomeClass\0id"
-         *
-         * We don't touch the key itself (so its s:N length stays valid).
-         * We only replace the *value* part: s:M:"123"  =>  i:123
-         */
         $alternatives = [];
         foreach ($keys as $k) {
-            // public
-            $alternatives[] = preg_quote($k, '/');
-            // protected
-            $alternatives[] = "\x00\\*\x00".preg_quote($k, '/');
-            // private (class-specific; we accept any class name between NULs)
-            $alternatives[] = "\x00[^\x00]+\x00".preg_quote($k, '/');
+            $alternatives[] = preg_quote($k, '/');                      // public
+            $alternatives[] = "\x00\\*\x00" . preg_quote($k, '/');      // protected
+            $alternatives[] = "\x00[^\x00]+\x00" . preg_quote($k, '/'); // private (any class)
         }
-        $nameAlt = '(?:'.implode('|', $alternatives).')';
+        $nameAlt = '(?:' . implode('|', $alternatives) . ')';
 
-        // Full pattern:
-        // (s:\d+:"<any of the above forms>";) s:\d+:"(<digits>)";
-        // Note: we *must not* use /u because of NUL bytes; keep binary-safe regex.
-        $pattern = '/(s:\d+:"'.$nameAlt.'";)s:\d+:"(\d+)";/s';
+        // Pattern: property name token, then value token -> coerce s:"123" to i:123
+        $pattern = '/(s:\d+:"' . $nameAlt . '";)s:\d+:"(\d+)";/s';
 
-        return preg_replace_callback(
+        $fixed = preg_replace_callback(
             $pattern,
-            static fn ($m) => $m[1].'i:'.$m[2].';',
+            static fn($m) => $m[1] . 'i:' . $m[2] . ';',
             $ser
         );
+
+        if ($fixed !== null && $fixed !== $ser) {
+            self::dlog('coerceNumericStrings.changed', ['delta_len' => strlen($fixed) - strlen($ser)]);
+            return $fixed;
+        }
+
+        self::dlog('coerceNumericStrings.no_change');
+        return $ser;
     }
 
     /**
-     * Recursively cast common identifier fields to int after unserialize.
-     * Safe to call on arrays/objects/stdClass/legacy resource objects.
+     * Recursively cast common identifier fields to int after unserialize (safe).
+     * - Never writes into private/protected properties (names starting with "\0").
+     * - Most coercion should happen *before* unserialize; this is a safety net.
      */
     private static function normalizeIds(mixed &$node): void
     {
         $castKeys = [
-            'id', 'iid', 'c_id', 'parent_id', 'thematic_id', 'attendance_id',
-            'room_id', 'display_order', 'session_id', 'category_id',
+            'id','iid','c_id','parent_id','thematic_id','attendance_id',
+            'room_id','display_order','session_id','category_id',
+            'forum_id','thread_id','post_id','survey_id','question_id',
+            'document_id','doc_id','link_id','quiz_id','work_id',
         ];
 
-        if (\is_array($node)) {
-            foreach ($node as $k => &$v) {
-                if (\is_string($k) && \in_array($k, $castKeys, true) && (\is_string($v) || is_numeric($v))) {
-                    $v = (int) $v;
-                } else {
-                    self::normalizeIds($v);
-                }
+        if (is_array($node)) {
+            foreach ($node as &$v) {
+                self::normalizeIds($v);
             }
-
             return;
         }
 
-        if (\is_object($node)) {
+        if (is_object($node)) {
             foreach (get_object_vars($node) as $k => $v) {
-                if (\in_array($k, $castKeys, true) && (\is_string($v) || is_numeric($v))) {
-                    $node->{$k} = (int) $v;
+                // Skip private/protected property names (start with NUL)
+                if (is_string($k) && $k !== '' && $k[0] === "\0") {
+                    self::normalizeIds($v);
+                    continue;
+                }
 
+                if (in_array($k, $castKeys, true) && (is_string($v) || is_numeric($v))) {
+                    try {
+                        $node->{$k} = (int) $v;
+                    } catch (Throwable) {
+                        // Read-only or typed mismatch: ignore
+                    }
                     continue;
                 }
+
                 self::normalizeIds($node->{$k});
             }
         }
     }
 
+    /**
+     * Replace any __PHP_Incomplete_Class instances with stdClass (deep).
+     * Also traverses arrays and objects.
+     */
+    private static function deincomplete(mixed $v): mixed
+    {
+        // Handle leaf
+        if ($v instanceof \__PHP_Incomplete_Class) {
+            $o = new \stdClass();
+            foreach (get_object_vars($v) as $k => $vv) {
+                $o->{$k} = self::deincomplete($vv);
+            }
+            return $o;
+        }
+        // Recurse arrays
+        if (is_array($v)) {
+            foreach ($v as $k => $vv) {
+                $v[$k] = self::deincomplete($vv);
+            }
+            return $v;
+        }
+        // Recurse stdClass or any object
+        if (is_object($v)) {
+            foreach (get_object_vars($v) as $k => $vv) {
+                $v->{$k} = self::deincomplete($vv);
+            }
+            return $v;
+        }
+        return $v;
+    }
+
     /**
      * Keep the old alias map so unserialize works exactly like v1.
      */
@@ -496,5 +680,7 @@ private static function registerLegacyAliases(): void
                 class_alias($fqcn, $alias);
             }
         }
+
+        self::dlog('registerLegacyAliases.done', ['count' => count($aliases)]);
     }
 }
diff --git a/src/CourseBundle/Component/CourseCopy/CourseBuilder.php b/src/CourseBundle/Component/CourseCopy/CourseBuilder.php
index 8ede7d7b6c9..97e945d1fe4 100644
--- a/src/CourseBundle/Component/CourseCopy/CourseBuilder.php
+++ b/src/CourseBundle/Component/CourseCopy/CourseBuilder.php
@@ -342,7 +342,6 @@ public function build(
 
         // Legacy DTO where resources[...] are built
         $legacyCourse = $this->course;
-
         foreach ($this->tools_to_build as $toolKey) {
             if (!empty($parseOnlyToolList)) {
                 $const = $this->toolToName[$toolKey] ?? null;
@@ -1947,7 +1946,8 @@ private function makeIdFilter(array $idsFilter): Closure
     }
 
     /**
-     * Export Tool intro (tool -> intro text) for visible tools.
+     * Export Tool intro only for the course_homepage tool.
+     * Prefers the session-specific intro when both (session and base) exist.
      */
     private function build_tool_intro(
         object $legacyCourse,
@@ -1960,39 +1960,59 @@ private function build_tool_intro(
 
         $repo = $this->em->getRepository(CToolIntro::class);
 
+        // Base query: join with tool, filter by course and the specific title
         $qb = $repo->createQueryBuilder('ti')
             ->innerJoin('ti.courseTool', 'ct')
             ->andWhere('ct.course = :course')
+            ->andWhere('ct.title = :title')
             ->setParameter('course', $courseEntity)
-        ;
+            ->setParameter('title', 'course_homepage');
 
+        // Session fallback: when a session is given, fetch both (session AND null)
         if ($sessionEntity) {
-            $qb->andWhere('ct.session = :session')->setParameter('session', $sessionEntity);
+            $qb->andWhere($qb->expr()->orX('ct.session = :session', 'ct.session IS NULL'))
+                ->setParameter('session', $sessionEntity);
         } else {
             $qb->andWhere('ct.session IS NULL');
         }
 
-        $qb->andWhere('ct.visibility = :vis')->setParameter('vis', true);
-
-        /** @var CToolIntro[] $intros */
-        $intros = $qb->getQuery()->getResult();
+        /** @var CToolIntro[] $rows */
+        $rows = $qb->getQuery()->getResult();
+        if (!$rows) {
+            return; // Nothing to export
+        }
 
-        foreach ($intros as $intro) {
-            $ctool = $intro->getCourseTool();       // CTool
-            $titleKey = (string) $ctool->getTitle();   // e.g. 'documents', 'forum'
-            if ('' === $titleKey) {
-                continue;
+        // Prefer the session-bound intro if present; otherwise, use the base (session IS NULL)
+        $selected = null;
+        foreach ($rows as $row) {
+            $tool = $row->getCourseTool();
+            if ($sessionEntity && $tool && $tool->getSession()) {
+                $selected = $row; // session-specific hit
+                break;
             }
+            if (!$selected) {
+                $selected = $row; // keep the base as fallback
+            }
+        }
 
-            $payload = [
-                'id' => $titleKey,
-                'intro_text' => (string) $intro->getIntroText(),
-            ];
+        if (!$selected) {
+            return;
+        }
 
-            // Use 0 as source_id (unused by restore)
-            $legacyCourse->resources[RESOURCE_TOOL_INTRO][$titleKey] =
-                $this->mkLegacyItem(RESOURCE_TOOL_INTRO, 0, $payload);
+        $ctool = $selected->getCourseTool();
+        $titleKey = (string) ($ctool?->getTitle() ?? 'course_homepage');
+        if ($titleKey === '') {
+            $titleKey = 'course_homepage'; // safety net
         }
+
+        $payload = [
+            'id'         => $titleKey,
+            'intro_text' => (string) $selected->getIntroText(),
+        ];
+
+        // Use 0 as source_id (unused by restore)
+        $legacyCourse->resources[RESOURCE_TOOL_INTRO][$titleKey] =
+            $this->mkLegacyItem(RESOURCE_TOOL_INTRO, 0, $payload);
     }
 
     /**
@@ -2196,49 +2216,55 @@ private function build_documents_with_repo(
             return;
         }
 
-        $qb = $this->docRepo->getResourcesByCourse(
-            $course,
-            $session,
-            null,
-            null,
-            true,
-            false
-        );
+        $qb = $this->docRepo->getResourcesByCourse($course, $session, null, null, true, false);
 
         if (!empty($idList)) {
             $qb->andWhere('resource.iid IN (:ids)')
-                ->setParameter('ids', array_values(array_unique(array_map('intval', $idList))))
-            ;
+                ->setParameter('ids', array_values(array_unique(array_map('intval', $idList))));
         }
 
         /** @var CDocument[] $docs */
         $docs = $qb->getQuery()->getResult();
 
+        $documentsRoot = $this->docRepo->getCourseDocumentsRootNode($course);
+
         foreach ($docs as $doc) {
-            $node = $doc->getResourceNode();
-            $filetype = $doc->getFiletype(); // 'file'|'folder'|...
-            $title = $doc->getTitle();
-            $comment = $doc->getComment() ?? '';
-            $iid = (int) $doc->getIid();
-            $fullPath = $doc->getFullPath();
-
-            // Determine size
+            $node     = $doc->getResourceNode();
+            $filetype = $doc->getFiletype(); // 'file' | 'folder' | ...
+            $title    = $doc->getTitle();
+            $comment  = $doc->getComment() ?? '';
+            $iid      = (int) $doc->getIid();
+
             $size = 0;
             if ('folder' === $filetype) {
                 $size = $this->docRepo->getFolderSize($node, $course, $session);
             } else {
-                /** @var Collection<int,ResourceFile>|null $files */
                 $files = $node?->getResourceFiles();
                 if ($files && $files->count() > 0) {
                     /** @var ResourceFile $first */
                     $first = $files->first();
-                    $size = (int) $first->getSize();
+                    $size  = (int) $first->getSize();
+                }
+            }
+
+            $rel = '';
+            if ($node instanceof ResourceNode) {
+                if ($documentsRoot instanceof ResourceNode) {
+                    $rel = $node->getPathForDisplayRemoveBase((string) $documentsRoot->getPath()); // e.g. "folder001/file.ext"
+                } else {
+                    $rel = $node->convertPathForDisplay((string) $node->getPath()); // e.g. "Documents/folder001/file.ext"
+                    $rel = preg_replace('~^/?Documents/?~i', '', (string) $rel) ?? $rel;
                 }
             }
+            $rel = trim((string) $rel, '/');
+            $pathForSelector = 'document' . ($rel !== '' ? '/'.$rel : '');
+            if ($filetype === 'folder') {
+                $pathForSelector = rtrim($pathForSelector, '/').'/';
+            }
 
             $exportDoc = new Document(
                 $iid,
-                '/'.$fullPath,
+                $pathForSelector,
                 $comment,
                 $title,
                 $filetype,
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ActivityExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ActivityExport.php
index e0f3f5a35c1..62ac4fd65ef 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ActivityExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ActivityExport.php
@@ -26,6 +26,8 @@ abstract class ActivityExport
      */
     protected $course;
 
+    public const DOCS_MODULE_ID = 1000000;
+
     public function __construct($course)
     {
         $this->course = $course;
@@ -131,42 +133,65 @@ protected function createGradesXml(array $data, string $directory): void
      */
     protected function createInforefXml(array $references, string $directory): void
     {
+        @error_log('[ActivityExport::createInforefXml] Start. Dir='.$directory);
+
         $xml = '<?xml version="1.0" encoding="UTF-8"?>'.PHP_EOL;
         $xml .= '<inforef>'.PHP_EOL;
 
+        $userCount = 0;
         if (!empty($references['users']) && \is_array($references['users'])) {
             $xml .= ' <userref>'.PHP_EOL;
             foreach ($references['users'] as $uid) {
                 $xml .= ' <user><id>'.htmlspecialchars((string) $uid).'</id></user>'.PHP_EOL;
+                $userCount++;
             }
             $xml .= ' </userref>'.PHP_EOL;
         }
 
+        $fileCount = 0;
+        $resolvedByHash = 0;
+
         if (!empty($references['files']) && \is_array($references['files'])) {
             $xml .= ' <fileref>'.PHP_EOL;
+
             foreach ($references['files'] as $file) {
                 $fid = null;
+                $hash = null;
+
                 if (\is_array($file)) {
-                    $fid = $file['id'] ?? null;
-                    $ch = $file['contenthash'] ?? null;
-                    if ($ch) {
-                        $resolved = FileIndex::resolveByContenthash((string) $ch);
-                        if (null !== $resolved) {
-                            $fid = $resolved;
+                    $fid  = $file['id'] ?? null;
+                    $hash = $file['contenthash'] ?? null;
+
+                    if ($hash) {
+                        $tmp = \Chamilo\CourseBundle\Component\CourseCopy\Moodle\Builder\FileIndex::resolveByContenthash((string) $hash);
+                        if (null !== $tmp) {
+                            $fid = $tmp;
+                            $resolvedByHash++;
+                        } else {
+                            @error_log('[ActivityExport::createInforefXml] WARNING: Could not resolve contenthash='.$hash.' to a file id.');
                         }
                     }
                 } else {
                     $fid = $file;
                 }
-                if (null !== $fid) {
-                    $xml .= ' <file><id>'.htmlspecialchars((string) $fid).'</id></file>'.PHP_EOL;
+
+                if (null === $fid) {
+                    @error_log('[ActivityExport::createInforefXml] WARNING: Null file id entry skipped.');
+                    continue;
                 }
+
+                $xml .= ' <file><id>'.htmlspecialchars((string) $fid).'</id></file>'.PHP_EOL;
+                $fileCount++;
             }
+
             $xml .= ' </fileref>'.PHP_EOL;
         }
 
         $xml .= '</inforef>'.PHP_EOL;
+
         $this->createXmlFile('inforef', $xml, $directory);
+
+        @error_log('[ActivityExport::createInforefXml] Done. users='.$userCount.' files='.$fileCount.' resolvedByHash='.$resolvedByHash.' Dir='.$directory);
     }
 
     /**
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/FolderExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/FolderExport.php
index 9e28062d737..88cfd44f8bb 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/FolderExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/FolderExport.php
@@ -24,22 +24,31 @@ class FolderExport extends ActivityExport
      */
     public function export($activityId, $exportDir, $moduleId, $sectionId): void
     {
-        // Prepare destination directory for the activity
+        @error_log('[FolderExport::export] Start. activityId='.(int)$activityId.' moduleId='.(int)$moduleId.' sectionId='.(int)$sectionId.' exportDir='.$exportDir);
+
         $folderDir = $this->prepareActivityDirectory($exportDir, 'folder', (int) $moduleId);
+        @error_log('[FolderExport::export] Activity dir='.$folderDir);
 
-        // Gather data
         $folderData = $this->getData((int) $activityId, (int) $sectionId);
+        if (!$folderData) {
+            @error_log('[FolderExport::export] ERROR: getData returned null for activityId='.$activityId);
+            return;
+        }
+
+        $refs = $this->getFilesForFolder((int) $activityId);
+        @error_log('[FolderExport::export] inforef files='.count($refs['files']).' users='.count($refs['users']));
 
-        // Generate activity files
         $this->createFolderXml($folderData, $folderDir);
         $this->createModuleXml($folderData, $folderDir);
         $this->createGradesXml($folderData, $folderDir);
         $this->createFiltersXml($folderData, $folderDir);
         $this->createGradeHistoryXml($folderData, $folderDir);
-        $this->createInforefXml($this->getFilesForFolder((int) $activityId), $folderDir);
+        $this->createInforefXml($refs, $folderDir);
         $this->createRolesXml($folderData, $folderDir);
         $this->createCommentsXml($folderData, $folderDir);
         $this->createCalendarXml($folderData, $folderDir);
+
+        @error_log('[FolderExport::export] Done. folderName='.$folderData['name'].' activityDir='.$folderDir);
     }
 
     /**
@@ -47,13 +56,12 @@ public function export($activityId, $exportDir, $moduleId, $sectionId): void
      */
     public function getData(int $folderId, int $sectionId): ?array
     {
-        // Virtual "Documents" folder at section level
         if (0 === $folderId) {
             return [
-                'id' => 0,
-                'moduleid' => 0,
+                'id' => ActivityExport::DOCS_MODULE_ID,
+                'moduleid' => ActivityExport::DOCS_MODULE_ID,
                 'modulename' => 'folder',
-                'contextid' => 0,
+                'contextid' => ActivityExport::DOCS_MODULE_ID,
                 'name' => 'Documents',
                 'sectionid' => $sectionId,
                 'sectionnumber' => 0,
@@ -63,7 +71,6 @@ public function getData(int $folderId, int $sectionId): ?array
             ];
         }
 
-        // Real folder coming from course resources
         $folder = $this->course->resources[RESOURCE_DOCUMENT][$folderId] ?? null;
         if (null === $folder) {
             return null;
@@ -114,6 +121,7 @@ private function createFolderXml(array $folderData, string $folderDir): void
      */
     private function getFilesForFolder(int $folderId): array
     {
+        @error_log('[FolderExport::getFilesForFolder] Start. folderId='.$folderId);
         $files = [];
 
         if (0 === $folderId) {
@@ -124,14 +132,16 @@ private function getFilesForFolder(int $folderId): array
                         'id' => (int) $doc->source_id,
                         'contenthash' => hash('sha1', basename((string) $doc->path)),
                         'filename' => basename((string) $doc->path),
-                        'filepath' => '/Documents/',
+                        'filepath' => '/', // <- CRÍTICO para Folder
                         'filesize' => (int) $doc->size,
                         'mimetype' => $this->getMimeType((string) $doc->path),
                     ];
                 }
             }
+            @error_log('[FolderExport::getFilesForFolder] Collected root docs='.count($files));
         }
 
+        @error_log('[FolderExport::getFilesForFolder] Done. Returning files='.count($files));
         return ['users' => [], 'files' => $files];
     }
 
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ForumExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ForumExport.php
index 0dfcc65556f..3c56abb8c88 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ForumExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/ForumExport.php
@@ -82,7 +82,7 @@ public function getData(int $forumId, int $sectionId): array
                             $msg = (string) ($post->obj->post_text ?? '');
                             $posts[] = [
                                 'id' => (int) ($post->obj->post_id ?? $postId),
-                                'parent' => (int) ($post->obj->parent_id ?? 0),
+                                'parent' => (int) ($post->obj->post_parent_id ?? $post->obj->parent_id ?? 0),
                                 'userid' => $adminId,
                                 'created' => $created,
                                 'modified' => $created,
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/PageExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/PageExport.php
index d8b95059ea1..cc3a49eb279 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Activities/PageExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Activities/PageExport.php
@@ -175,13 +175,10 @@ private function createPageXml(array $pageData, string $pageDir): void
 
     /**
      * Normalize HTML content by rewriting course document URLs to @@PLUGINFILE@@ tokens.
-     * Covers:
-     *  - <img src="..."> (existing behavior)
-     *  - <a href="...">
-     *  - <link href="...">
-     *  - <source src="..."> (audio/video)
-     *  - poster="..." on <video>
-     *  - url(...) in inline style="" and <style> blocks.
+     * Now also handles:
+     *  - srcset="... 1x, ... 2x" on <img>
+     *  - data="..." (e.g. <object data="...">)
+     * Existing behaviors for src|href|poster, inline styles and <style> remain.
      */
     private function normalizeContent(string $html): string
     {
@@ -189,9 +186,42 @@ private function normalizeContent(string $html): string
             return $html;
         }
 
-        // 1) Generic attributes: src|href|poster on any tag
+        // 0) Handle srcset specifically (multiple candidates)
         $html = (string) preg_replace_callback(
-            '~\b(src|href|poster)\s*=\s*([\'"])([^\'"]+)\2~i',
+            '~\bsrcset\s*=\s*([\'"])(.*?)\1~is',
+            function (array $m): string {
+                $q = $m[1];
+                $val = $m[2];
+
+                // Split by commas but keep descriptors (e.g., "image@2x.png 2x")
+                $parts = array_map('trim', explode(',', $val));
+                foreach ($parts as &$p) {
+                    if ('' === $p) {
+                        continue;
+                    }
+                    // First token is the URL, the rest (if any) are descriptors
+                    // e.g., "foo.png 2x" -> ["foo.png","2x"]
+                    $tokens = preg_split('/\s+/', $p, -1, PREG_SPLIT_NO_EMPTY);
+                    if (empty($tokens)) {
+                        continue;
+                    }
+                    $url = $tokens[0];
+                    $new = $this->rewriteDocUrl($url);
+                    if ($new !== $url) {
+                        $tokens[0] = $new;
+                        $p = implode(' ', $tokens);
+                    }
+                }
+                $newVal = implode(', ', $parts);
+
+                return 'srcset='.$q.$newVal.$q;
+            },
+            $html
+        );
+
+        // 1) Generic attributes: src|href|poster|data on any tag
+        $html = (string) preg_replace_callback(
+            '~\b(src|href|poster|data)\s*=\s*([\'"])([^\'"]+)\2~i',
             function (array $m): string {
                 $attr = $m[1];
                 $q = $m[2];
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/FileExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/FileExport.php
index 97223c2bcba..b837c6f75ba 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/FileExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/FileExport.php
@@ -7,6 +7,7 @@
 namespace Chamilo\CourseBundle\Component\CourseCopy\Moodle\Builder;
 
 use Chamilo\CoreBundle\Framework\Container;
+use Chamilo\CourseBundle\Component\CourseCopy\Moodle\Activities\ActivityExport;
 use Chamilo\CourseBundle\Entity\CDocument;
 use DocumentManager;
 use Exception;
@@ -25,6 +26,18 @@ class FileExport
      */
     private $course;
 
+    /**
+     * Module context id for the mod_folder activity inside the backup.
+     * Default kept for safety; MoodleExport must override via setModuleContextId().
+     */
+    private int $moduleContextId = 1000000;
+
+    /**
+     * Keep legacy folder-children traversal but disabled by default to avoid duplicates.
+     * You can re-enable via setUseFolderTraversal(true) without losing this code path.
+     */
+    private bool $useFolderTraversal = false;
+
     /**
      * Constructor to initialize course data.
      *
@@ -35,50 +48,92 @@ public function __construct(object $course)
         $this->course = $course;
     }
 
+    /**
+     * Allow caller (MoodleExport) to set the real context id of the created mod_folder activity.
+     */
+    public function setModuleContextId(int $ctx): void
+    {
+        // INFO: caller should pass the module's context placeholder id from activities/folder_* (e.g. 1000000)
+        $this->moduleContextId = $ctx;
+        @error_log('[FileExport] Module context id set to '.$this->moduleContextId);
+    }
+
+    /**
+     * Keep legacy folder-children traversal available (OFF by default).
+     * Turning it on may create duplicates, but dedupe will catch them.
+     */
+    public function setUseFolderTraversal(bool $on): void
+    {
+        $this->useFolderTraversal = $on;
+        @error_log('[FileExport] Use folder traversal = '.($on ? 'true' : 'false'));
+    }
+
     /**
      * Export files and metadata from files.xml to the specified directory.
      */
     public function exportFiles(array $filesData, string $exportDir): void
     {
+        @error_log('[FileExport::exportFiles] Start. exportDir='.$exportDir.' inputCount='.(int)count($filesData['files'] ?? []));
+
         $filesDir = $exportDir.'/files';
         if (!is_dir($filesDir)) {
             mkdir($filesDir, api_get_permissions_for_new_directories(), true);
+            @error_log('[FileExport::exportFiles] Created dir '.$filesDir);
         }
         $this->createPlaceholderFile($filesDir);
 
         $unique = ['files' => []];
-        $seenKeys = []; // string => true
+        $seenKeys = [];
 
-        foreach (($filesData['files'] ?? []) as $file) {
-            $ch = (string) ($file['contenthash'] ?? '');
-            $comp = (string) ($file['component'] ?? '');
-            $area = (string) ($file['filearea'] ?? '');
+        $dedupSkipped = 0;
+        $badPaths = 0;
+
+        foreach (($filesData['files'] ?? []) as $idx => $file) {
+            // Normalize every row to what Moodle restore expects for mod_folder
+            $file = $this->normalizeRow($file);
+
+            $ch   = (string) ($file['contenthash'] ?? '');
             $path = $this->ensureTrailingSlash((string) ($file['filepath'] ?? '/'));
             $name = (string) ($file['filename'] ?? '');
 
             if ('' === $ch || '' === $name) {
+                @error_log('[FileExport::exportFiles] WARNING: Skipping entry idx='.$idx.' (missing contenthash or filename).');
                 continue;
             }
 
-            $dedupeKey = implode('|', [$ch, $comp, $area, $path, $name]);
+            // Dedupe across sources (do NOT include component/filearea/contextid to actually remove duplicates)
+            $dedupeKey = implode('|', [$ch, $path, $name]);
             if (isset($seenKeys[$dedupeKey])) {
+                $dedupSkipped++;
                 continue;
             }
             $seenKeys[$dedupeKey] = true;
 
+            // register for inforef resolution
             FileIndex::register($file);
 
+            if (strpos($path, '/Documents/') === 0) {
+                $badPaths++;
+                @error_log('[FileExport::exportFiles] WARNING: filepath starts with /Documents/ (Moodle folder expects /). filepath='.$path.' filename='.$name);
+            }
+
             $file['filepath'] = $path;
             $unique['files'][] = $file;
         }
 
-        foreach ($unique['files'] as $file) {
-            $ch = (string) $file['contenthash'];
+        @error_log('[FileExport::exportFiles] After dedupe: '.count($unique['files']).' file(s). dedupSkipped='.$dedupSkipped.' badPathsDetected='.$badPaths);
+
+        $copied = 0;
+        foreach ($unique['files'] as $f) {
+            $ch = (string) $f['contenthash'];
             $subdir = FileIndex::resolveSubdirByContenthash($ch);
-            $this->copyFileToExportDir($file, $filesDir, $subdir);
+            $this->copyFileToExportDir($f, $filesDir, $subdir);
+            $copied++;
         }
+        @error_log('[FileExport::exportFiles] Copied payloads: '.$copied);
 
         $this->createFilesXml($unique, $exportDir);
+        @error_log('[FileExport::exportFiles] Done.');
     }
 
     /**
@@ -135,26 +190,29 @@ public function getFilesData(): array
                     continue;
                 }
 
-                $filesData['files'][] = [
-                    'id' => $docId,
-                    'contenthash' => hash('sha1', basename($docData['path'])),
-                    'contextid' => (int) ($this->course->info['real_id'] ?? 0),
-                    'component' => 'mod_assign',
-                    'filearea' => 'introattachment',
-                    'itemid' => (int) ($work->params['id'] ?? 0),
-                    'filepath' => '/Documents/',
+                $row = [
+                    'id'           => $docId,
+                    'contenthash'  => hash('sha1', basename($docData['path'])),
+                    'contextid'    => (int) ($this->course->info['real_id'] ?? 0), // will be normalized to moduleContextId
+                    'component'    => 'mod_assign', // will be normalized to mod_folder
+                    'filearea'     => 'introattachment', // will be normalized to content
+                    'itemid'       => (int) ($work->params['id'] ?? 0), // will be normalized to 0
+                    'filepath'     => '/Documents/', // will be normalized
                     'documentpath' => 'document/'.$docData['path'],
-                    'filename' => basename($docData['path']),
-                    'userid' => $adminId,
-                    'filesize' => (int) ($docData['size'] ?? 0),
-                    'mimetype' => $this->getMimeType($docData['path']),
-                    'status' => 0,
-                    'timecreated' => time() - 3600,
+                    'filename'     => basename($docData['path']),
+                    'userid'       => $adminId,
+                    'filesize'     => (int) ($docData['size'] ?? 0),
+                    'mimetype'     => $this->getMimeType($docData['path']),
+                    'status'       => 0,
+                    'timecreated'  => time() - 3600,
                     'timemodified' => time(),
-                    'source' => (string) ($docData['title'] ?? ''),
-                    'author' => 'Unknown',
-                    'license' => 'allrightsreserved',
+                    'source'       => (string) ($docData['title'] ?? ''),
+                    'author'       => 'Unknown',
+                    'license'      => 'allrightsreserved',
                 ];
+
+                // Normalize to folder activity before pushing
+                $filesData['files'][] = $this->normalizeRow($row);
             }
         }
 
@@ -177,7 +235,9 @@ private function createPlaceholderFile(string $filesDir): void
      */
     private function copyFileToExportDir(array $file, string $filesDir, ?string $precomputedSubdir = null): void
     {
-        if (($file['filepath'] ?? '.') === '.') {
+        $fp = (string)($file['filepath'] ?? '.');
+        if ($fp === '.') {
+            @error_log('[FileExport::copyFileToExportDir] Skipping file with filepath dot. id='.(int)($file['id'] ?? 0));
             return;
         }
 
@@ -187,6 +247,7 @@ private function copyFileToExportDir(array $file, string $filesDir, ?string $pre
 
         if (!is_dir($exportSubDir)) {
             mkdir($exportSubDir, api_get_permissions_for_new_directories(), true);
+            @error_log('[FileExport::copyFileToExportDir] Created subdir '.$exportSubDir);
         }
 
         $destinationFile = $exportSubDir.'/'.$contenthash;
@@ -198,9 +259,16 @@ private function copyFileToExportDir(array $file, string $filesDir, ?string $pre
 
         if (is_file($filePath)) {
             if (!is_file($destinationFile)) {
-                copy($filePath, $destinationFile);
+                if (@copy($filePath, $destinationFile)) {
+                    @error_log('[FileExport::copyFileToExportDir] OK copy id='.(int)($file['id'] ?? 0).' -> '.$destinationFile);
+                } else {
+                    @error_log('[FileExport::copyFileToExportDir] ERROR copy failed id='.(int)($file['id'] ?? 0).' src='.$filePath.' dst='.$destinationFile);
+                }
+            } else {
+                @error_log('[FileExport::copyFileToExportDir] Already exists dst='.$destinationFile);
             }
         } else {
+            @error_log('[FileExport::copyFileToExportDir] ERROR source not found: '.$filePath.' (id='.(int)($file['id'] ?? 0).')');
             throw new Exception("Source file not found: {$filePath}");
         }
     }
@@ -212,15 +280,45 @@ private function copyFileToExportDir(array $file, string $filesDir, ?string $pre
      */
     private function createFilesXml(array $filesData, string $destinationDir): void
     {
+        @error_log('[FileExport::createFilesXml] Start. destinationDir='.$destinationDir);
+
         $xmlContent = '<?xml version="1.0" encoding="UTF-8"?>'.PHP_EOL;
         $xmlContent .= '<files>'.PHP_EOL;
 
+        $total = 0;
+        $modFolder = 0;
+        $badFilepath = 0;
+        $wrongItemId = 0;
+
         foreach (($filesData['files'] ?? []) as $file) {
+            // Safety: ensure already-normalized rows
+            $file = $this->normalizeRow($file);
+
             $xmlContent .= $this->createFileXmlEntry($file);
+            $total++;
+
+            $comp = (string)($file['component'] ?? '');
+            $area = (string)($file['filearea'] ?? '');
+            $fp   = (string)($file['filepath'] ?? '');
+            $it   = (int)($file['itemid'] ?? 0);
+
+            if ($comp === 'mod_folder' && $area === 'content') {
+                $modFolder++;
+                if ($fp === '' || $fp[0] !== '/' || substr($fp, -1) !== '/') {
+                    $badFilepath++;
+                    @error_log('[FileExport::createFilesXml] WARNING bad filepath (must start/end with /): id='.(int)($file['id'] ?? 0).' filepath='.$fp);
+                }
+                if ($it !== 0) {
+                    $wrongItemId++;
+                    @error_log('[FileExport::createFilesXml] WARNING itemid must be 0 for mod_folder/content id='.(int)($file['id'] ?? 0).' itemid='.$it);
+                }
+            }
         }
 
         $xmlContent .= '</files>'.PHP_EOL;
         file_put_contents($destinationDir.'/files.xml', $xmlContent);
+
+        @error_log('[FileExport::createFilesXml] Done. total='.$total.' mod_folder='.$modFolder.' badFilepath='.$badFilepath.' wrongItemId='.$wrongItemId);
     }
 
     /**
@@ -268,43 +366,141 @@ private function processDocument(array $filesData, object $document): array
             && isset($this->course->used_page_doc_ids)
             && \in_array($document->source_id, (array) $this->course->used_page_doc_ids, true)
         ) {
+            @error_log('[FileExport::processDocument] Skipping file id='.$document->source_id.' (used by PageExport)');
             return $filesData;
         }
 
         // Skip top-level HTML documents that are exported as Page
         if (
             ($document->file_type ?? null) === 'file'
-            && 'html' === pathinfo($document->path, PATHINFO_EXTENSION)
+            && 'html' === strtolower((string)pathinfo($document->path, PATHINFO_EXTENSION))
             && 1 === substr_count($document->path, '/')
         ) {
+            @error_log('[FileExport::processDocument] Skipping top-level HTML (will be Page) id='.$document->source_id);
             return $filesData;
         }
 
+        // Simple FILE -> becomes part of Folder activity
         if (($document->file_type ?? null) === 'file') {
             $extension = strtolower((string) pathinfo($document->path, PATHINFO_EXTENSION));
             if (!\in_array($extension, ['html', 'htm'], true)) {
                 $fileData = $this->getFileData($document);
-                $fileData['filepath'] = '/Documents/';
-                $fileData['contextid'] = 0;
-                $fileData['component'] = 'mod_folder';
+
+                // Derive hierarchical folder path inside moodle folder content
+                [$filepath, /*$fn*/, $rest] = $this->deriveRelativeDirAndName((string)$document->path);
+                $fileData['filepath']  = $filepath;          // "/folder001/" or "/folder001/subfolder 001/" or "/"
+
+                // Normalize to mod_folder + moduleContextId
+                $fileData = $this->normalizeRow($fileData);
+
+                @error_log('[FileExport::processDocument] FILE id='.$fileData['id'].' rest='.$rest.' -> fp='.$fileData['filepath'].' name='.$fileData['filename']);
+
                 $filesData['files'][] = $fileData;
             }
         } elseif (($document->file_type ?? null) === 'folder') {
+            if (!$this->useFolderTraversal) {
+                @error_log('[FileExport::processDocument] INFO: folder traversal disabled, skipping folder iid='.(int)$document->source_id.' (kept code for compatibility)');
+                return $filesData;
+            }
+
             $docRepo = Container::getDocumentRepository();
             $folderFiles = $docRepo->listFilesByParentIid((int) $document->source_id);
 
+            @error_log('[FileExport::processDocument] FOLDER iid='.(int)$document->source_id.' contains '.count($folderFiles).' file(s)');
+
             foreach ($folderFiles as $file) {
-                $filesData['files'][] = $this->getFolderFileData(
+                [$filepath, $fn, $rest] = $this->deriveRelativeDirAndName((string)($file['path'] ?? ''));
+
+                $row = $this->getFolderFileData(
                     $file,
-                    (int) $document->source_id,
-                    '/Documents/'.\dirname($file['path']).'/'
+                    (int)$document->source_id,
+                    $filepath
                 );
+
+                // Normalize to mod_folder + moduleContextId
+                $row = $this->normalizeRow($row);
+
+                @error_log('[FileExport::processDocument] CHILD id='.$row['id'].' rest='.$rest.' -> fp='.$row['filepath'].' name='.$row['filename']);
+
+                $filesData['files'][] = $row;
             }
         }
 
         return $filesData;
     }
 
+    /**
+     * Normalize one row to Moodle mod_folder/content requirements.
+     * - component=mod_folder
+     * - filearea=content
+     * - itemid=0
+     * - contextid=$this->moduleContextId
+     * - filepath normalized, never "/Documents/"
+     */
+    private function normalizeRow(array $row): array
+    {
+        $row['component'] = 'mod_folder';
+        $row['filearea']  = 'content';
+        $row['itemid']    = 0;
+        $row['contextid'] = $this->moduleContextId;
+
+        $fp = (string)($row['filepath'] ?? '/');
+        if ($fp === '' || $fp === '.' || $fp === '/') {
+            $fp = '/';
+        } else {
+            // convert legacy /Documents/... to /
+            if (strpos($fp, '/Documents/') === 0) {
+                $fp = '/';
+            }
+        }
+        $row['filepath'] = $this->ensureTrailingSlash($fp);
+
+        // Safety: filename must never be empty
+        $row['filename'] = (string)($row['filename'] ?? '');
+        if ($row['filename'] === '') {
+            $row['filename'] = 'unnamed';
+        }
+
+        return $row;
+    }
+
+    private function deriveRelativeDirAndName(string $absolutePath): array
+    {
+        $code = (string)($this->course->code ?? '');
+        $raw  = str_replace('\\', '/', $absolutePath);
+        $raw  = ltrim($raw, '/');
+
+        // Look for the course code segment and take the remainder
+        if (preg_match('#(?:^|/)'.preg_quote($code, '#').'/+(.*)$#', $raw, $m)) {
+            $rest = $m[1]; // e.g. "folder001/subfolder 001/settings-changed.odt"
+        } else {
+            // Fallback: trim common prefixes document/document/localhost/...
+            $rest = preg_replace('#^document/(?:document/)?(?:[^/]+/)?#', '', $raw);
+        }
+
+        $rest     = trim((string)$rest, '/');
+        $filename = basename($rest);
+        $dir      = trim((string)dirname($rest), '.');
+
+        $filepath = ($dir === '' || $dir === '/') ? '/' : '/'.$dir.'/';
+
+        @error_log('[FileExport::deriveRelativeDirAndName] code='.$code.' raw='.$absolutePath.' rest='.$rest.' dir='.$dir.' -> filepath='.$filepath.' filename='.$filename);
+
+        return [$filepath, $filename, $rest];
+    }
+
+    private function normalizeMoodleFilepath(string $path): string
+    {
+        $path = str_replace('\\', '/', trim($path));
+        if ($path === '' || $path === '.' || $path === '/') {
+            return '/';
+        }
+        $path = ltrim($path, '/');
+        $path = (string)preg_replace('#/+#', '/', $path);
+        $path = trim($path, '/');
+        return '/'.$path.'/';
+    }
+
     /**
      * Get file data for a single document.
      *
@@ -331,11 +527,11 @@ private function getFileData(object $document): array
         return [
             'id' => (int) $document->source_id,
             'contenthash' => $contenthash,
-            'contextid' => (int) $document->source_id,
-            'component' => 'mod_resource',
-            'filearea' => 'content',
-            'itemid' => (int) $document->source_id,
-            'filepath' => '/',
+            'contextid' => (int) $document->source_id, // will be normalized to moduleContextId
+            'component' => 'mod_resource',             // will be normalized to mod_folder
+            'filearea' => 'content',                   // will be normalized (kept for compatibility)
+            'itemid' => (int) $document->source_id,    // will be normalized to 0
+            'filepath' => '/',                         // will be replaced by deriveRelativeDirAndName()
             'documentpath' => (string) $document->path,
             'filename' => basename($document->path),
             'userid' => $adminId,
@@ -353,42 +549,43 @@ private function getFileData(object $document): array
     }
 
     /**
-     * Get file data for files inside a folder.
+     * Get file data for files inside a folder (legacy flow preserved).
      *
      * @param array<string,mixed> $file
      *
      * @return array<string,mixed>
      */
-    private function getFolderFileData(array $file, int $sourceId, string $parentPath = '/Documents/'): array
+    private function getFolderFileData(array $file, int $sourceId, string $parentPath = '/'): array
     {
         $adminData = MoodleExport::getAdminUserData();
         $adminId = $adminData['id'] ?? 0;
 
-        $contenthash = hash('sha1', basename($file['path']));
-        $mimetype = $this->getMimeType($file['path']);
-        $filename = basename($file['path']);
-        $filepath = $this->ensureTrailingSlash($parentPath);
+        $contenthash = hash('sha1', basename((string) $file['path']));
+        $mimetype    = $this->getMimeType((string) $file['path']);
+        $filename    = basename((string) $file['path']);
+
+        $filepath = $this->normalizeMoodleFilepath($parentPath);
 
         return [
-            'id' => (int) $file['id'],
+            'id'          => (int) ($file['id'] ?? 0),
             'contenthash' => $contenthash,
-            'contextid' => $sourceId,
-            'component' => 'mod_folder',
-            'filearea' => 'content',
-            'itemid' => (int) $file['id'],
-            'filepath' => $filepath,
-            'documentpath' => 'document/'.$file['path'],
-            'filename' => $filename,
-            'userid' => $adminId,
-            'filesize' => (int) $file['size'],
-            'mimetype' => $mimetype,
-            'status' => 0,
+            'contextid'   => $sourceId, // will be normalized to moduleContextId
+            'component'   => 'mod_folder',
+            'filearea'    => 'content',
+            'itemid'      => (int) ($file['id'] ?? 0), // will be normalized to 0
+            'filepath'    => $filepath,
+            'documentpath'=> 'document/'.$file['path'],
+            'filename'    => $filename,
+            'userid'      => $adminId,
+            'filesize'    => (int) ($file['size'] ?? 0),
+            'mimetype'    => $mimetype,
+            'status'      => 0,
             'timecreated' => time() - 3600,
-            'timemodified' => time(),
-            'source' => (string) $file['title'],
-            'author' => 'Unknown',
-            'license' => 'allrightsreserved',
-            'abs_path' => $file['abs_path'] ?? null,
+            'timemodified'=> time(),
+            'source'      => (string) ($file['title'] ?? ''),
+            'author'      => 'Unknown',
+            'license'     => 'allrightsreserved',
+            'abs_path'    => $file['abs_path'] ?? null,
         ];
     }
 
@@ -397,12 +594,14 @@ private function getFolderFileData(array $file, int $sourceId, string $parentPat
      */
     private function ensureTrailingSlash(string $path): string
     {
-        if ('' === $path || '.' === $path || '/' === $path) {
+        // Normalize slashes and remove '/./'
+        $path = (string) str_replace('\\', '/', $path);
+        $path = (string) preg_replace('#/\./#', '/', $path);
+        $path = (string) preg_replace('#/+#', '/', $path);
+
+        if ($path === '' || $path === '.' || $path === '/') {
             return '/';
         }
-
-        $path = (string) preg_replace('/\/+/', '/', $path);
-
         return rtrim($path, '/').'/';
     }
 
@@ -441,6 +640,7 @@ private function getMimeTypes(): array
             'pptx' => 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
             'zip' => 'application/zip',
             'rar' => 'application/x-rar-compressed',
+            'wav' => 'audio/wav',
         ];
     }
 }
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleExport.php
index 5b4d80f26a7..89d64991a2e 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleExport.php
@@ -7,6 +7,7 @@
 namespace Chamilo\CourseBundle\Component\CourseCopy\Moodle\Builder;
 
 use Chamilo\CourseBundle\Component\CourseCopy\CourseBuilder;
+use Chamilo\CourseBundle\Component\CourseCopy\Moodle\Activities\ActivityExport;
 use Chamilo\CourseBundle\Component\CourseCopy\Moodle\Activities\AssignExport;
 use Chamilo\CourseBundle\Component\CourseCopy\Moodle\Activities\FeedbackExport;
 use Chamilo\CourseBundle\Component\CourseCopy\Moodle\Activities\ForumExport;
@@ -77,53 +78,82 @@ public function __construct(object $course, bool $selectionMode = false)
      */
     public function export(string $courseId, string $exportDir, int $version)
     {
+        @error_log('[MoodleExport::export] Start. courseId='.$courseId.' exportDir='.$exportDir.' version='.$version);
+
         $tempDir = api_get_path(SYS_ARCHIVE_PATH).$exportDir;
 
         if (!is_dir($tempDir)) {
             if (!mkdir($tempDir, api_get_permissions_for_new_directories(), true)) {
+                @error_log('[MoodleExport::export] ERROR cannot create tempDir='.$tempDir);
                 throw new Exception(get_lang('ErrorCreatingDirectory'));
             }
+            @error_log('[MoodleExport::export] Created tempDir='.$tempDir);
         }
 
         $courseInfo = api_get_course_info($courseId);
         if (!$courseInfo) {
+            @error_log('[MoodleExport::export] ERROR CourseNotFound id='.$courseId);
             throw new Exception(get_lang('CourseNotFound'));
         }
 
-        // Generate the moodle_backup.xml
+        // 1) Create Moodle backup skeleton (backup.xml + dirs)
         $this->createMoodleBackupXml($tempDir, $version);
+        @error_log('[MoodleExport::export] moodle_backup.xml generated');
+
+        // 2) <<< INSERT HERE >>> Enqueue URL activities before collecting all activities
+        //    We build URL activities from the "link" bucket and push them into the pipeline.
+        //    This must happen BEFORE calling getActivities() so they are included.
+        if (method_exists($this, 'enqueueUrlActivities')) {
+            @error_log('[MoodleExport::export] Enqueuing URL activities …');
+            $this->enqueueUrlActivities();
+            @error_log('[MoodleExport::export] URL activities enqueued');
+        } else {
+            @error_log('[MoodleExport::export][WARN] enqueueUrlActivities() not found; skipping URL activities');
+        }
 
-        // Get the activities from the course
+        // 3) Gather activities (now includes URLs)
         $activities = $this->getActivities();
+        @error_log('[MoodleExport::export] Activities count='.count($activities));
 
-        // Export course-related files
+        // 4) Export course structure (sections + activities metadata)
         $courseExport = new CourseExport($this->course, $activities);
         $courseExport->exportCourse($tempDir);
+        @error_log('[MoodleExport::export] course/ exported');
 
-        // Export files-related data and actual files
+        // 5) Page export (collect extra files from HTML pages)
         $pageExport = new PageExport($this->course);
         $pageFiles = [];
         $pageData = $pageExport->getData(0, 1);
         if (!empty($pageData['files'])) {
             $pageFiles = $pageData['files'];
         }
+        @error_log('[MoodleExport::export] pageFiles from PageExport='.count($pageFiles));
+
+        // 6) Files export (documents, attachments, + pages’ files)
         $fileExport = new FileExport($this->course);
         $filesData = $fileExport->getFilesData();
-        $filesData['files'] = array_merge($filesData['files'], $pageFiles);
+        @error_log('[MoodleExport::export] getFilesData='.count($filesData['files'] ?? []));
+        $filesData['files'] = array_merge($filesData['files'] ?? [], $pageFiles);
+        @error_log('[MoodleExport::export] merged files='.count($filesData['files'] ?? []));
         $fileExport->exportFiles($filesData, $tempDir);
 
-        // Export sections of the course
+        // 7) Sections export (topics/weeks descriptors)
         $this->exportSections($tempDir);
+        @error_log('[MoodleExport::export] sections/ exported');
 
-        // Export all root XML files
+        // 8) Root XMLs (course/activities indexes)
         $this->exportRootXmlFiles($tempDir);
+        @error_log('[MoodleExport::export] root XMLs exported');
 
-        // Compress everything into a .mbz (ZIP) file
+        // 9) Create .mbz archive
         $exportedFile = $this->createMbzFile($tempDir);
+        @error_log('[MoodleExport::export] mbz created at '.$exportedFile);
 
-        // Clean up temporary directory
+        // 10) Cleanup temp dir
         $this->cleanupTempDir($tempDir);
+        @error_log('[MoodleExport::export] tempDir removed '.$tempDir);
 
+        @error_log('[MoodleExport::export] Done. file='.$exportedFile);
         return $exportedFile;
     }
 
@@ -500,31 +530,33 @@ private function getSections(): array
         return $sections;
     }
 
+    // src/.../MoodleExport.php
     private function getActivities(): array
     {
+        @error_log('[MoodleExport::getActivities] Start');
+
         $activities = [];
         $glossaryAdded = false;
 
-        // Safely resolve the documents bucket (accept constant or plain 'document')
+        // Build a "documents" bucket (root-level files/folders)
         $docBucket = [];
         if (\defined('RESOURCE_DOCUMENT') && isset($this->course->resources[RESOURCE_DOCUMENT]) && \is_array($this->course->resources[RESOURCE_DOCUMENT])) {
             $docBucket = $this->course->resources[RESOURCE_DOCUMENT];
         } elseif (isset($this->course->resources['document']) && \is_array($this->course->resources['document'])) {
             $docBucket = $this->course->resources['document'];
         }
+        @error_log('[MoodleExport::getActivities] docBucket='.count($docBucket));
 
-        // If there are documents selected/present, add a visible "folder" activity like before
+        // Add a visible "Documents" folder activity if we actually have documents
         if (!empty($docBucket)) {
-            // NOTE: This creates the visible Folder activity in Moodle that groups all documents.
-            // Files themselves will also be exported by FileExport as usual.
-            $documentsFolder = [
-                'id' => 0,
+            $activities[] = [
+                'id'        => ActivityExport::DOCS_MODULE_ID,
                 'sectionid' => 0,
-                'modulename' => 'folder',
-                'moduleid' => 0,
-                'title' => 'Documents',
+                'modulename'=> 'folder',
+                'moduleid'  => ActivityExport::DOCS_MODULE_ID,
+                'title'     => 'Documents',
             ];
-            $activities[] = $documentsFolder;
+            @error_log('[MoodleExport::getActivities] Added visible folder activity "Documents" (moduleid=' . ActivityExport::DOCS_MODULE_ID . ').');
         }
 
         $htmlPageIds = [];
@@ -540,7 +572,7 @@ private function getActivities(): array
                 $title = '';
                 $id = 0;
 
-                // QUIZ
+                // Quiz
                 if (RESOURCE_QUIZ === $resourceType && ($resource->obj->iid ?? 0) > 0) {
                     $exportClass = QuizExport::class;
                     $moduleName = 'quiz';
@@ -548,14 +580,14 @@ private function getActivities(): array
                     $title = (string) $resource->obj->title;
                 }
 
-                // URL (Link)
+                // URL
                 if (RESOURCE_LINK === $resourceType && ($resource->source_id ?? 0) > 0) {
                     $exportClass = UrlExport::class;
                     $moduleName = 'url';
                     $id = (int) $resource->source_id;
                     $title = (string) ($resource->title ?? '');
                 }
-                // GLOSSARY (only once)
+                // Glossary (only once)
                 elseif (RESOURCE_GLOSSARY === $resourceType && ($resource->glossary_id ?? 0) > 0 && !$glossaryAdded) {
                     $exportClass = GlossaryExport::class;
                     $moduleName = 'glossary';
@@ -563,24 +595,23 @@ private function getActivities(): array
                     $title = get_lang('Glossary');
                     $glossaryAdded = true;
                 }
-                // FORUM
+                // Forum
                 elseif (RESOURCE_FORUM === $resourceType && ($resource->source_id ?? 0) > 0) {
                     $exportClass = ForumExport::class;
                     $moduleName = 'forum';
                     $id = (int) ($resource->obj->iid ?? 0);
                     $title = (string) ($resource->obj->forum_title ?? '');
                 }
-                // DOCUMENT → page/resource only when it really qualifies
+                // Documents (as Page or Resource)
                 elseif (RESOURCE_DOCUMENT === $resourceType && ($resource->source_id ?? 0) > 0) {
                     $resPath = (string) ($resource->path ?? '');
                     $resTitle = (string) ($resource->title ?? '');
                     $fileType = (string) ($resource->file_type ?? '');
 
-                    // Root = only one slash (e.g., "/foo.pdf")
                     $isRoot = ('' !== $resPath && 1 === substr_count($resPath, '/'));
                     $ext = '' !== $resPath ? pathinfo($resPath, PATHINFO_EXTENSION) : '';
 
-                    // Root HTML becomes a Moodle 'page'
+                    // Root HTML -> export as "page"
                     if ('html' === $ext && $isRoot) {
                         $exportClass = PageExport::class;
                         $moduleName = 'page';
@@ -589,7 +620,7 @@ private function getActivities(): array
                         $htmlPageIds[] = $id;
                     }
 
-                    // Root FILE (not already exported as 'page') becomes a Moodle 'resource'
+                    // Regular file -> export as "resource" (avoid colliding with pages)
                     if ('file' === $fileType && !\in_array($resource->source_id, $htmlPageIds, true)) {
                         $resourceExport = new ResourceExport($this->course);
                         if ($resourceExport->getSectionIdForActivity((int) $resource->source_id, $resourceType) > 0) {
@@ -602,21 +633,26 @@ private function getActivities(): array
                         }
                     }
                 }
-                // COURSE INTRO
-                elseif (RESOURCE_TOOL_INTRO === $resourceType && ($resource->source_id ?? '') === 'course_homepage') {
-                    $exportClass = PageExport::class;
-                    $moduleName = 'page';
-                    $id = 0;
-                    $title = get_lang('Introduction');
+                // *** Tool Intro -> treat "course_homepage" as a Page activity (id=0) ***
+                elseif (RESOURCE_TOOL_INTRO === $resourceType) {
+                    // IMPORTANT: do not check source_id; the real key is obj->id
+                    $objId = (string) ($resource->obj->id ?? '');
+                    if ($objId === 'course_homepage') {
+                        $exportClass = PageExport::class;
+                        $moduleName = 'page';
+                        // Keep activity id = 0 → PageExport::getData(0, ...) reads the intro HTML
+                        $id = 0;
+                        $title = get_lang('Introduction');
+                    }
                 }
-                // ASSIGN
+                // Assignments
                 elseif (RESOURCE_WORK === $resourceType && ($resource->source_id ?? 0) > 0) {
                     $exportClass = AssignExport::class;
                     $moduleName = 'assign';
                     $id = (int) $resource->source_id;
                     $title = (string) ($resource->params['title'] ?? '');
                 }
-                // FEEDBACK (Survey)
+                // Surveys -> Feedback
                 elseif (RESOURCE_SURVEY === $resourceType && ($resource->source_id ?? 0) > 0) {
                     $exportClass = FeedbackExport::class;
                     $moduleName = 'feedback';
@@ -624,23 +660,143 @@ private function getActivities(): array
                     $title = (string) ($resource->params['title'] ?? '');
                 }
 
+                // Emit activity if resolved
                 if ($exportClass && $moduleName) {
                     /** @var object $exportInstance */
                     $exportInstance = new $exportClass($this->course);
+                    $sectionId = $exportInstance->getSectionIdForActivity($id, $resourceType);
                     $activities[] = [
                         'id' => $id,
-                        'sectionid' => $exportInstance->getSectionIdForActivity($id, $resourceType),
+                        'sectionid' => $sectionId,
                         'modulename' => $moduleName,
                         'moduleid' => $id,
                         'title' => $title,
                     ];
+                    @error_log('[MoodleExport::getActivities] ADD modulename='.$moduleName.' moduleid='.$id.' sectionid='.$sectionId.' title="'.str_replace(["\n","\r"],' ',$title).'"');
                 }
             }
         }
 
+        @error_log('[MoodleExport::getActivities] Done. total='.count($activities));
         return $activities;
     }
 
+    /**
+     * Collect Moodle URL activities from legacy "link" bucket.
+     *
+     * It is defensive against different wrappers:
+     * - Accepts link objects as $wrap->obj or directly as $wrap.
+     * - Resolves title from title|name|url (last-resort).
+     * - Maps category_id to a section name (category title) if available.
+     *
+     * @return UrlExport[]
+     */
+    private function buildUrlActivities(): array
+    {
+        $res = \is_array($this->course->resources ?? null) ? $this->course->resources : [];
+
+        // Buckets (defensive: allow legacy casings)
+        $links = $res['link'] ?? $res['Link'] ?? [];
+        $cats  = $res['link_category'] ?? $res['Link_Category'] ?? [];
+
+        // Map category_id → label for section naming
+        $catLabel = [];
+        foreach ($cats as $cid => $cwrap) {
+            if (!\is_object($cwrap)) {
+                continue;
+            }
+            $c = (isset($cwrap->obj) && \is_object($cwrap->obj)) ? $cwrap->obj : $cwrap;
+            $label = '';
+            foreach (['title', 'name'] as $k) {
+                if (!empty($c->{$k}) && \is_string($c->{$k})) {
+                    $label = trim((string) $c->{$k});
+                    break;
+                }
+            }
+            $catLabel[(int) $cid] = $label !== '' ? $label : ('Category #'.(int) $cid);
+        }
+
+        $out = [];
+        foreach ($links as $id => $lwrap) {
+            if (!\is_object($lwrap)) {
+                continue;
+            }
+            $L = (isset($lwrap->obj) && \is_object($lwrap->obj)) ? $lwrap->obj : $lwrap;
+
+            $url = (string) ($L->url ?? '');
+            if ($url === '') {
+                // Skip invalid URL records
+                continue;
+            }
+
+            // Resolve a robust title
+            $title = '';
+            foreach (['title', 'name'] as $k) {
+                if (!empty($L->{$k}) && \is_string($L->{$k})) {
+                    $title = trim((string) $L->{$k});
+                    break;
+                }
+            }
+            if ($title === '') {
+                $title = $url; // last resort: use the URL itself
+            }
+
+            $target = (string) ($L->target ?? '');
+            $intro  = (string) ($L->description ?? '');
+            $cid    = (int) ($L->category_id ?? 0);
+
+            $sectionName = $catLabel[$cid] ?? null;
+
+            // UrlExport ctor: (string $title, string $url, ?string $section = null, ?string $introHtml = null, ?string $target = null)
+            $urlAct = new UrlExport($title, $url, $sectionName ?: null, $intro ?: null, $target ?: null);
+            if (method_exists($urlAct, 'setLegacyId')) {
+                $urlAct->setLegacyId((int) $id);
+            }
+
+            $out[] = $urlAct;
+        }
+
+        return $out;
+    }
+
+    /**
+     * Enqueue all URL activities into the export pipeline.
+     * Will try queueActivity(), then addActivity(), then $this->activities[].
+     */
+    private function enqueueUrlActivities(): void
+    {
+        $urls = $this->buildUrlActivities();
+
+        if (empty($urls)) {
+            @error_log('[MoodleExport] No URL activities to enqueue');
+            return;
+        }
+
+        if (method_exists($this, 'queueActivity')) {
+            foreach ($urls as $act) {
+                $this->queueActivity($act);
+            }
+            @error_log('[MoodleExport] URL activities enqueued via queueActivity(): '.count($urls));
+            return;
+        }
+
+        if (method_exists($this, 'addActivity')) {
+            foreach ($urls as $act) {
+                $this->addActivity($act);
+            }
+            @error_log('[MoodleExport] URL activities appended via addActivity(): '.count($urls));
+            return;
+        }
+
+        if (property_exists($this, 'activities') && \is_array($this->activities)) {
+            array_push($this->activities, ...$urls);
+            @error_log('[MoodleExport] URL activities appended to $this->activities: '.count($urls));
+            return;
+        }
+
+        @error_log('[MoodleExport][WARN] Could not enqueue URL activities (no compatible method found)');
+    }
+
     private function exportSections(string $exportDir): void
     {
         $sections = $this->getSections();
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleImport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleImport.php
index 42a3967f647..09ca87ba307 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleImport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/MoodleImport.php
@@ -516,6 +516,9 @@ private function readHtmlModule(string $xmlPath, string $type): array
             ?? $xp->query('//content')->item(0)?->nodeValue
             ?? '');
 
+        // NEW: normalize @@PLUGINFILE@@ placeholders so local files resolve
+        $content = $this->normalizePluginfileContent($content);
+
         return [
             'name' => $name,
             'content' => $content,
@@ -2022,4 +2025,24 @@ private function mkLegacyItem(string $type, int $sourceId, array|object $obj, ar
 
         return $o;
     }
+
+    /**
+     * Replace Moodle @@PLUGINFILE@@ placeholders with package-local /document/ URLs
+     * so that later HTML URL mapping can resolve and rewire them correctly.
+     * Examples:
+     *   @@PLUGINFILE@@/Documents/foo.png  -> /document/foo.png
+     *   @@PLUGINFILE@@/documents/bar.pdf  -> /document/bar.pdf
+     */
+    private function normalizePluginfileContent(string $html): string
+    {
+        if ('' === $html) {
+            return $html;
+        }
+
+        // Case-insensitive replace; keep a single leading slash
+        // Handles both Documents/ and documents/
+        $html = preg_replace('~@@PLUGINFILE@@/(?:Documents|documents)/~i', '/document/', $html);
+
+        return $html;
+    }
 }
diff --git a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/SectionExport.php b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/SectionExport.php
index 1fbcff3aa82..75f8ae7d801 100644
--- a/src/CourseBundle/Component/CourseCopy/Moodle/Builder/SectionExport.php
+++ b/src/CourseBundle/Component/CourseCopy/Moodle/Builder/SectionExport.php
@@ -82,32 +82,66 @@ public function getGeneralItems(): array
     {
         $generalItems = [];
 
+        // Map legacy resource types to their primary identifier field
         $resourceTypes = [
-            RESOURCE_DOCUMENT => 'source_id',
-            RESOURCE_QUIZ => 'source_id',
-            RESOURCE_GLOSSARY => 'glossary_id',
-            RESOURCE_LINK => 'source_id',
-            RESOURCE_WORK => 'source_id',
-            RESOURCE_FORUM => 'source_id',
-            RESOURCE_SURVEY => 'source_id',
-            RESOURCE_TOOL_INTRO => 'source_id',
+            RESOURCE_DOCUMENT    => 'source_id',
+            RESOURCE_QUIZ        => 'source_id',
+            RESOURCE_GLOSSARY    => 'glossary_id',
+            RESOURCE_LINK        => 'source_id',
+            RESOURCE_WORK        => 'source_id',
+            RESOURCE_FORUM       => 'source_id',
+            RESOURCE_SURVEY      => 'source_id',
+            RESOURCE_TOOL_INTRO  => 'source_id',
         ];
 
         foreach ($resourceTypes as $resourceType => $idKey) {
-            if (!empty($this->course->resources[$resourceType])) {
-                foreach ($this->course->resources[$resourceType] as $id => $resource) {
-                    if (!$this->isItemInLearnpath($resource, (string) $resourceType)) {
-                        $title = RESOURCE_WORK === $resourceType
-                            ? ($resource->params['title'] ?? '')
-                            : ($resource->title ?? $resource->name);
+            if (empty($this->course->resources[$resourceType]) || !\is_array($this->course->resources[$resourceType])) {
+                continue;
+            }
+
+            foreach ($this->course->resources[$resourceType] as $bagKey => $resource) {
+                // Skip items that are already part of a learnpath
+                if ($this->isItemInLearnpath($resource, (string) $resourceType)) {
+                    continue;
+                }
+
+                // --- Special case: Tool intro as course homepage → export as Moodle "page" (id=0) ---
+                if (RESOURCE_TOOL_INTRO === $resourceType) {
+                    // We rely on obj->id === 'course_homepage'
+                    $objId = (string) ($resource->obj->id ?? '');
+                    if ('course_homepage' === $objId) {
                         $generalItems[] = [
-                            'id' => $resource->{$idKey},
-                            'item_type' => $resourceType,
-                            'path' => $id,
-                            'title' => $title,
+                            // Keep this literal so downstream code can detect it easily
+                            'id'        => 'course_homepage',
+                            'item_type' => 'page', // already normalized for addActivityToList()
+                            'path'      => 0,      // PageExport::getData(0, ...) will read intro HTML
+                            'title'     => get_lang('Introduction'),
                         ];
                     }
+                    // Do not add any other tool-intro variants here
+                    continue;
+                }
+
+                // --- Default handling for other resource types ---
+                // Robust title resolution (avoid notices if properties are missing)
+                $title =
+                    (RESOURCE_WORK === $resourceType)
+                        ? (string) ($resource->params['title'] ?? ($resource->title ?? ''))
+                        : (string) ($resource->title ?? ($resource->name ?? ''));
+
+                // Resolve the primary id safely; skip if missing (defensive)
+                $primaryId = $resource->{$idKey} ?? null;
+                if (null === $primaryId) {
+                    // Defensive log could be added here if needed
+                    continue;
                 }
+
+                $generalItems[] = [
+                    'id'        => $primaryId,
+                    'item_type' => $resourceType,
+                    'path'      => $bagKey,
+                    'title'     => $title,
+                ];
             }
         }
 
diff --git a/src/CourseBundle/Component/CourseCopy/Resources/GradeBookBackup.php b/src/CourseBundle/Component/CourseCopy/Resources/GradeBookBackup.php
index f16dd5fd080..9744d462b6c 100644
--- a/src/CourseBundle/Component/CourseCopy/Resources/GradeBookBackup.php
+++ b/src/CourseBundle/Component/CourseCopy/Resources/GradeBookBackup.php
@@ -7,27 +7,44 @@
 namespace Chamilo\CourseBundle\Component\CourseCopy\Resources;
 
 /**
- * Class GradeBookBackup.
+ * Class GradeBookBackup
+ *
+ * Represents a Gradebook resource snapshot for copy/export operations.
+ * NOTE: This class extends Resource and MUST keep method signatures compatible.
  */
 class GradeBookBackup extends Resource
 {
-    public $categories;
+    /**
+     * Categories included in this gradebook backup.
+     *
+     * @var array<int, mixed>
+     */
+    public array $categories;
 
     /**
-     * @param array $categories
+     * Constructor.
+     *
+     * @param array<int, mixed> $categories Categories to be included.
      */
-    public function __construct($categories)
+    public function __construct(array $categories)
     {
-        parent::__construct(uniqid(), RESOURCE_GRADEBOOK);
+        // Use a unique id and the proper resource type constant.
+        // uniqid with more_entropy=true minimizes collision risk.
+        parent::__construct(uniqid('', true), RESOURCE_GRADEBOOK);
         $this->categories = $categories;
     }
 
     /**
-     * @return void
+     * Render the gradebook backup summary.
+     * IMPORTANT: Keep signature compatible with parent: Resource::show(): void
      */
     public function show(): void
     {
+        // Call parent show (if it performs common rendering/initialization).
         parent::show();
+
+        // Do not return any value here; echo/print or set properties instead.
+        // Keep user-facing text retrievable via get_lang for localization.
         echo get_lang('All');
     }
 }