diff --git a/tests/tine20/Filemanager/Frontend/WebDAVTest.php b/tests/tine20/Filemanager/Frontend/WebDAVTest.php
index 56439e162b4..cb67351f6e3 100644
--- a/tests/tine20/Filemanager/Frontend/WebDAVTest.php
+++ b/tests/tine20/Filemanager/Frontend/WebDAVTest.php
@@ -146,7 +146,7 @@ protected function _testGetNodeForPath_webdav_filemanagerWithOtherUsers($propert
         $fs->setGrantsForNode($personalFolder, $personalFolder->grants);
 
         $children = $node->getChildren();
-
+        
         static::assertGreaterThanOrEqual(3, count($children));
         static::assertInstanceOf('Filemanager_Frontend_WebDAV', $children[0], 'wrong node class');
         $names = [];
@@ -159,6 +159,192 @@ protected function _testGetNodeForPath_webdav_filemanagerWithOtherUsers($propert
         static::assertEquals(1, count(array_intersect($names, [$sclever->{$property}])));
     }
 
+    /**
+     * should not change default personal grants
+     */
+    public function testGetNodeForPath_webdav_filemanagerWithoutGrants_currentUser()
+    {
+        $nodeFsRootPath = '/webdav/Filemanager';
+ 
+        // try to get folder /user , should always sync
+        // it doesn't check grants in \Tinebase_WebDav_Collection_AbstractContainerTree::_getUser
+        $children = $this->_getNewWebDAVTreeNode($nodeFsRootPath)->getChildren();
+        static::assertCount(2, $children, 'child root nodes should always be sync');
+        
+        // try to get folder /user/personal, should always sync
+        // check grants in \Tinebase_WebDav_Collection_AbstractContainerTree::_getSharedChildren
+        $nodeUserRootPath = $nodeFsRootPath . '/'. Tinebase_Core::getUser()->accountDisplayName;
+        $children = $this->_getNewWebDAVTreeNode($nodeUserRootPath)->getChildren();
+        static::assertCount(1, $children, 'child node personal default should be sync');
+
+        // try to get folder /user/personal/dir1
+        // check grants in \Tinebase_Frontend_WebDAV_Directory::getChildren
+        $nodeUserRoot = $this->_getNewWebDAVTreeNode($nodeUserRootPath);
+        $nodeUserDefault = current($nodeUserRoot->getChildren());
+        $nodeUserDefault->createDirectory('dir1');
+        $nodeUserDefaultPath = $nodeUserRootPath . '/' . $nodeUserDefault->getName();
+        $children = $this->_getNewWebDAVTreeNode($nodeUserDefaultPath)->getChildren();
+        static::assertCount(1, $children, 'child node dir1 should be sync');
+        
+        // try to get folder /user/personal/dir1/dir2
+        // check grants in \Tinebase_Frontend_WebDAV_Directory::getChildren
+        $nodeDir1 = current($nodeUserDefault->getChildren());
+        $nodeDir1->createDirectory('dir2');
+        $nodeDir1Path = $nodeUserDefaultPath . '/' . $nodeDir1->getName();
+        $children = $this->_getNewWebDAVTreeNode($nodeDir1Path)->getChildren();
+        static::assertCount(1, $children, 'child node dir2 should be sync');
+    }
+
+    /**
+     * @throws Tinebase_Exception_NotFound
+     * @throws \Sabre\DAV\Exception\NotFound
+     */
+    public function testGetNodeForPath_webdav_filemanagerWithoutGrants_otherUser()
+    {
+        $nodeFsRootPath = '/webdav/Filemanager';
+  
+        // try to get folder /user
+        // check grants in \Filemanager_Frontend_WebDAV::_getOtherUsersChildren
+        $treeNodeUserRootPath = Tinebase_FileSystem::getInstance()->getApplicationBasePath('Filemanager', Tinebase_FileSystem::FOLDER_TYPE_PERSONAL) . '/' .
+            Tinebase_Core::getUser()->getId();
+        $treeNodeUserRoot = Tinebase_FileSystem::getInstance()->stat($treeNodeUserRootPath);
+        $treeNodeUserDefault = Tinebase_FileSystem::getInstance()->getTreeNodeChildren($treeNodeUserRoot)->getFirstRecord();
+        $this->_testGrantsHelper($treeNodeUserDefault, $nodeFsRootPath);
+
+        // try to get folder /user/personal ,
+        // check grants in \Tinebase_WebDav_Collection_AbstractContainerTree::_getSharedChildren
+        $nodeUserRootPath = $nodeFsRootPath . '/'. Tinebase_Core::getUser()->accountDisplayName;
+        $this->_testGrantsHelper($treeNodeUserDefault, $nodeUserRootPath);
+
+        // try to get folder /user/personal/dir1
+        // check grants in \Tinebase_Frontend_WebDAV_Directory::getChildren
+        $nodeUserRoot = $this->_getNewWebDAVTreeNode($nodeUserRootPath);
+        $nodeUserDefault = current($nodeUserRoot->getChildren());
+        $nodeUserDefaultPath = $nodeUserRootPath . '/' . $nodeUserDefault->getName();
+        $nodeUserDefault->createDirectory('dir1');
+        $treeNodeDir1 = Tinebase_FileSystem::getInstance()->getTreeNodeChildren($treeNodeUserDefault)->getFirstRecord();
+        $this->_testGrantsHelper($treeNodeDir1, $nodeUserDefaultPath);
+
+        // try to get folder /user/personal/dir1/dir2
+        // check grants in \Tinebase_Frontend_WebDAV_Directory::getChildren
+        $nodeDir1 = current($nodeUserDefault->getChildren());
+        $nodeDir1->createDirectory('dir2');
+        $nodeDir1Path = $nodeUserDefaultPath . '/' . $nodeDir1->getName();
+        $treeNodeDir2 = Tinebase_FileSystem::getInstance()->getTreeNodeChildren($treeNodeDir1)->getFirstRecord();
+        $this->_testGrantsHelper($treeNodeDir2, $nodeDir1Path);
+    }
+
+    /**
+     * @throws Tinebase_Exception_NotFound
+     * @throws \Sabre\DAV\Exception\NotFound
+     */
+    public function testGetNodeForPath_webdav_filemanagerWithoutGrants_shared()
+    {
+        $nodeFsRootPath = '/webdav/Filemanager';
+        // try to get folder /shared , should always sync and ignore grants setting
+        $children = $this->_getNewWebDAVTreeNode($nodeFsRootPath)->getChildren();
+        static::assertCount(2, $children, 'child root nodes should always be sync');
+        
+        // try to get folder /shared/dir1
+        // check grants in \Tinebase_WebDav_Collection_AbstractContainerTree::_getSharedDirectories
+        $nodeSharedRootPath = $nodeFsRootPath . '/'. 'shared';
+        $nodeSharedRoot = $this->_getNewWebDAVTreeNode($nodeSharedRootPath);
+        $nodeSharedRoot->createDirectory('dir1');
+        $treeNodeSharedRootPath = Tinebase_FileSystem::getInstance()->getApplicationBasePath('Filemanager', Tinebase_FileSystem::FOLDER_TYPE_SHARED);
+        $treeNodeSharedRoot = Tinebase_FileSystem::getInstance()->stat($treeNodeSharedRootPath);
+        $treeNodeDir1 = Tinebase_FileSystem::getInstance()->getTreeNodeChildren($treeNodeSharedRoot)->getFirstRecord();
+        $this->_testGrantsHelper($treeNodeDir1, $nodeSharedRootPath);
+
+        // try to get folder /shared/dir1/dir2
+        // check grants in \Tinebase_Frontend_WebDAV_Directory::getChildren
+        $nodeDir1 = current($nodeSharedRoot->getChildren());
+        $nodeDir1->createDirectory('dir2');
+        $nodeDir1Path = $nodeSharedRootPath . '/' . $nodeDir1->getName();
+        $treeNodeDir2 = Tinebase_FileSystem::getInstance()->getTreeNodeChildren($treeNodeDir1)->getFirstRecord();
+        $this->_testGrantsHelper($treeNodeDir2, $nodeDir1Path);
+    }
+
+    /**
+     * node should only be sync when user has both READ_GRANT and SYNC_GRANT
+     * 
+     * @throws Tinebase_Exception_NotFound
+     * @throws \Sabre\DAV\Exception\NotFound
+     */
+    protected function _testGrantsHelper($folder, $nodePath, $isForcedSyncNode = false)
+    {
+        $testSyncUser = $this->_personas['sclever'];
+        $hideNodesCount = ! $isForcedSyncNode ? 1 : 0;
+        
+        // set default grant for test sync user first
+        Tinebase_Tree_NodeGrants::getInstance()->getGrantsForRecord($folder);
+        if (isset($folder['grants'])) {
+            $folder->grants->addRecord(new Tinebase_Model_Grants([
+                'account_type' => Tinebase_Acl_Rights::ACCOUNT_TYPE_USER,
+                'account_id' => $testSyncUser->getId(),
+                Tinebase_Model_Grants::GRANT_ADMIN => true
+            ]));
+            Tinebase_FileSystem::getInstance()->setGrantsForNode($folder, $folder->grants);
+        }
+        
+        // change current user to test the sync ability
+        Tinebase_Core::setUser($testSyncUser);
+        $expectChildren = $this->_getNewWebDAVTreeNode($nodePath)->getChildren();
+        $expectChildCount = count($expectChildren);
+
+        // assert sync only without read_grant nor sync_grant
+        foreach ($folder->grants as $grant) {
+            if ($grant->account_id === $testSyncUser->getId() || $grant->account_type === Tinebase_Acl_Rights::ACCOUNT_TYPE_GROUP) {
+                $grant->adminGrant = false;
+                $grant->syncGrant = false;
+                $grant->readGrant = false;
+            }
+        }
+        Tinebase_FileSystem::getInstance()->setGrantsForNode($folder, $folder->grants);
+        $children = $this->_getNewWebDAVTreeNode($nodePath)->getChildren();
+        static::assertCount($expectChildCount - $hideNodesCount, $children, 'children node should not be sync');
+
+        // assert sync only with read_grant or sync_grant
+        foreach ($folder->grants as $grant) {
+            if ($grant->account_id === $testSyncUser->getId()) {
+                $grant['syncGrant'] = false;
+                $grant['readGrant'] = true;
+            }
+        }
+        Tinebase_FileSystem::getInstance()->setGrantsForNode($folder, $folder->grants);
+        $children = $this->_getNewWebDAVTreeNode($nodePath)->getChildren();
+        static::assertCount($expectChildCount - $hideNodesCount, $children, 'children node should not be sync');
+
+        foreach ($folder->grants as $grant) {
+            if ($grant->account_id === $testSyncUser->getId()) {
+                $grant['syncGrant'] = true;
+                $grant['readGrant'] = false;
+            }
+        }
+        Tinebase_FileSystem::getInstance()->setGrantsForNode($folder, $folder->grants);
+        $children = $this->_getNewWebDAVTreeNode($nodePath)->getChildren();
+        static::assertCount($expectChildCount - $hideNodesCount, $children, 'children node should not be sync');
+
+        // assert sync only with both read_grant and sync_grant
+        foreach ( $folder->grants as $grant) {
+            if ($grant->account_id === $testSyncUser->getId()) {
+                $grant['syncGrant'] = true;
+                $grant['readGrant'] = true;
+            }
+        }
+        Tinebase_FileSystem::getInstance()->setGrantsForNode($folder, $folder->grants);
+        $children = $this->_getNewWebDAVTreeNode($nodePath)->getChildren();
+        static::assertCount($expectChildCount, $children, 'children node should be sync');
+
+        // reset current user and folder grants for operating nodes
+        Tinebase_Core::setUser($this->_originalTestUser);
+        
+        foreach ( $folder->grants as $grant) {
+            if ($grant->account_id === $testSyncUser->getId()) {
+                $folder->grants->removeRecord($grant);
+            }
+        }
+    }
+
     public function testGetNodeForPath_webdav_filemanagerWithOtherUsersLoginName()
     {
         Tinebase_Config::getInstance()->set(Tinebase_Config::USE_LOGINNAME_AS_FOLDERNAME, true);
@@ -1014,4 +1200,15 @@ protected function _getWebDAVTree()
         
         return $this->_webdavTree;
     }
+
+    /**
+     *
+     * @return \Sabre\DAV\ICollection|\Sabre\DAV\INode|\Sabre\DAV\ObjectTree
+     */
+    protected function _getNewWebDAVTreeNode($path)
+    {   
+        $node = new Tinebase_WebDav_ObjectTree(new Tinebase_WebDav_Root());
+        $node = $node->getNodeForPath($path);
+        return $node;
+    }
 }
diff --git a/tine20/Filemanager/Frontend/WebDAV.php b/tine20/Filemanager/Frontend/WebDAV.php
index f6e5a550b35..02875b0722f 100644
--- a/tine20/Filemanager/Frontend/WebDAV.php
+++ b/tine20/Filemanager/Frontend/WebDAV.php
@@ -104,7 +104,7 @@ protected function _getOtherUsersChildren()
     {
         $children = array();
         foreach (Tinebase_FileSystem::getInstance()->getOtherUsers(Tinebase_Core::getUser(),
-                $this->_getApplicationName(), [Tinebase_Model_Grants::GRANT_READ, Tinebase_Model_Grants::GRANT_SYNC]) as
+                $this->_getApplicationName(), [Tinebase_Model_Grants::GRANT_READ, '&' . Tinebase_Model_Grants::GRANT_SYNC]) as
                 $node) {
             $name = $node->name;
             // we never use id as name!
diff --git a/tine20/Tinebase/Container.php b/tine20/Tinebase/Container.php
index 5bf35ea16cb..2649cc50123 100644
--- a/tine20/Tinebase/Container.php
+++ b/tine20/Tinebase/Container.php
@@ -807,19 +807,20 @@ public static function addGrantsSql($_select, $_accountId, $_grant, $_aclTableNa
         // enforce string for pgsql
         array_walk($roleMemberships, function(&$item) {$item = (string)$item;});
 
-        $quotedActId   = $db->quoteIdentifier("{$_aclTableName}.account_id");
-        $quotedActType = $db->quoteIdentifier("{$_aclTableName}.account_type");
-        
-        $accountSelect = new Tinebase_Backend_Sql_Filter_GroupSelect($_select);
-        $accountSelect
-            ->orWhere("{$quotedActId} = ? AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_USER), $accountId)
-            ->orWhere("{$quotedActId} IN (?) AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_GROUP), empty($groupMemberships) ? ' ' : $groupMemberships)
-            ->orWhere("{$quotedActId} IN (?) AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_ROLE), empty($roleMemberships) ? ' ' : $roleMemberships);
+        $accountSelectFunc = function($quotedActId, $quotedActType) use($_select, $db, $accountId, $groupMemberships, $roleMemberships) {
+            $accountSelect = new Tinebase_Backend_Sql_Filter_GroupSelect($_select);
+            $accountSelect
+                ->orWhere("{$quotedActId} = ? AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_USER), $accountId)
+                ->orWhere("{$quotedActId} IN (?) AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_GROUP), empty($groupMemberships) ? ' ' : $groupMemberships)
+                ->orWhere("{$quotedActId} IN (?) AND {$quotedActType} = " . $db->quote(Tinebase_Acl_Rights::ACCOUNT_TYPE_ROLE), empty($roleMemberships) ? ' ' : $roleMemberships);
+
+            if (!Tinebase_Config::getInstance()->get(Tinebase_Config::ANYONE_ACCOUNT_DISABLED)) {
+                $accountSelect->orWhere("{$quotedActType} = ?", Tinebase_Acl_Rights::ACCOUNT_TYPE_ANYONE);
+            }
+            $accountSelect->appendWhere(Zend_Db_Select::SQL_AND);
+        };
         
-        if (! Tinebase_Config::getInstance()->get(Tinebase_Config::ANYONE_ACCOUNT_DISABLED)) {
-            $accountSelect->orWhere("{$quotedActType} = ?", Tinebase_Acl_Rights::ACCOUNT_TYPE_ANYONE);
-        }
-        $accountSelect->appendWhere(Zend_Db_Select::SQL_AND);
+        $accountSelectFunc($db->quoteIdentifier("{$_aclTableName}.account_id"), $db->quoteIdentifier("{$_aclTableName}.account_type"));
         
         // we only need to filter, if the filter does not contain %
         if (!in_array('*', $grants)) {
@@ -833,6 +834,7 @@ public static function addGrantsSql($_select, $_accountId, $_grant, $_aclTableNa
             }
             $iteration = 0;
             $grantsSelect = new Tinebase_Backend_Sql_Filter_GroupSelect($_select);
+            $grantsSelect->openBracket();
             foreach ($grants as $grant) {
                 if ($grant[0] === '(') {
                     $grantsSelect->openBracket();
@@ -858,6 +860,7 @@ public static function addGrantsSql($_select, $_accountId, $_grant, $_aclTableNa
                     if ($iteration > 0) {
                         $callbackIdentifier = call_user_func($joinCallBack, $_select, $iteration);
                         $grantsSelect->where($db->quoteIdentifier($callbackIdentifier . '.account_grant') . ' LIKE ?', $grant);
+                        $accountSelectFunc($db->quoteIdentifier("{$callbackIdentifier}.account_id"), $db->quoteIdentifier("{$callbackIdentifier}.account_type"));
                     } else {
                         $grantsSelect->where($quotedGrant . ' LIKE ?', $grant);
                     }
@@ -869,6 +872,7 @@ public static function addGrantsSql($_select, $_accountId, $_grant, $_aclTableNa
                     $grantsSelect->closeBracket();
                 }
             }
+            $grantsSelect->closeBracket();
 
             // admin grant includes all other grants
             if (! in_array(Tinebase_Model_Grants::GRANT_ADMIN, $grants)) {
diff --git a/tine20/Tinebase/Frontend/WebDAV/Directory.php b/tine20/Tinebase/Frontend/WebDAV/Directory.php
index 734fa5e01df..d3352917c54 100644
--- a/tine20/Tinebase/Frontend/WebDAV/Directory.php
+++ b/tine20/Tinebase/Frontend/WebDAV/Directory.php
@@ -44,7 +44,10 @@ public function getChildren()
         // Loop through the directory, and create objects for each node
         try {
             foreach (Tinebase_FileSystem::getInstance()->scanDir($this->_path) as $node) {
-                $children[] = $this->getChild($node->name);
+                if (Tinebase_Core::getUser()->hasGrant($node, Tinebase_Model_Grants::GRANT_READ) 
+                    && Tinebase_Core::getUser()->hasGrant($node, Tinebase_Model_Grants::GRANT_SYNC)) {
+                    $children[] = $this->getChild($node->name);
+                }
             }
         } catch (Tinebase_Exception_NotFound $tenf) {
             throw new Sabre\DAV\Exception\NotFound('path not found: ' . $this->_path);
diff --git a/tine20/Tinebase/Model/Filter/GrantsFilterGroup.php b/tine20/Tinebase/Model/Filter/GrantsFilterGroup.php
index d45b730b5be..d5bcdd89d67 100644
--- a/tine20/Tinebase/Model/Filter/GrantsFilterGroup.php
+++ b/tine20/Tinebase/Model/Filter/GrantsFilterGroup.php
@@ -91,7 +91,7 @@ public function appendFilterSql($select, $backend)
             $this->_tempBackend = null;
         }
         
-        if (Tinebase_Core::isLogLevel(Zend_Log::TRACE)) Tinebase_Core::getLogger()->trace(__METHOD__ . '::' . __LINE__ 
+        if (Tinebase_Core::isLogLevel(Zend_Log::DEBUG)) Tinebase_Core::getLogger()->debug(__METHOD__ . '::' . __LINE__ 
             . ' $select after appending grants sql: ' . $select);
     }
 
@@ -106,7 +106,7 @@ public function addGrantsSqlCallback($_select, $iteration)
     {
         $db = $_select->getAdapter();
         $tblAlias = $this->_aclTableName . $iteration;
-        $_select->join(array(
+        $_select->joinLeft(array(
             /* table  */ $tblAlias => SQL_TABLE_PREFIX . $this->_aclTableName),
             /* on     */ $db->quoteIdentifier($tblAlias . '.record_id') . ' = ' . $db->quoteIdentifier($this->_tempBackend->getTableName() . '.' . $this->_aclIdColumn),
             array()
diff --git a/tine20/Tinebase/WebDav/Collection/AbstractContainerTree.php b/tine20/Tinebase/WebDav/Collection/AbstractContainerTree.php
index 7696b3899ac..d247cf0b9be 100644
--- a/tine20/Tinebase/WebDav/Collection/AbstractContainerTree.php
+++ b/tine20/Tinebase/WebDav/Collection/AbstractContainerTree.php
@@ -551,7 +551,7 @@ protected function _getOtherUsersChildren()
         // TODO allow NODES here
         $otherUsers = Tinebase_Container::getInstance()->getOtherUsers(Tinebase_Core::getUser(), $this->_getApplicationName(), array(
             Tinebase_Model_Grants::GRANT_READ,
-            Tinebase_Model_Grants::GRANT_SYNC
+            '&' . Tinebase_Model_Grants::GRANT_SYNC
         ));
 
         foreach ($otherUsers as $user) {
@@ -597,14 +597,14 @@ protected function _getSharedChildren()
                         $accountId,
                         array(
                             Tinebase_Model_Grants::GRANT_READ,
-                            Tinebase_Model_Grants::GRANT_SYNC
+                            '&' . Tinebase_Model_Grants::GRANT_SYNC
                         )
                     );
                 } else {
                     // NOTE: seems to be the expected behavior for non-delegation clients
                     $containers = $this->_containerController->getContainerByACL(Tinebase_Core::getUser(), $this->_model, array(
                         Tinebase_Model_Grants::GRANT_READ,
-                        Tinebase_Model_Grants::GRANT_SYNC
+                        '&' . Tinebase_Model_Grants::GRANT_SYNC
                     ));
                 }
             } catch (Tinebase_Exception_AccessDenied $tead) {
@@ -635,7 +635,7 @@ protected function _getSharedDirectories()
             $this->_model ?: $this->_getApplicationName(),
             array(
                 Tinebase_Model_Grants::GRANT_READ,
-                Tinebase_Model_Grants::GRANT_SYNC
+                '&' . Tinebase_Model_Grants::GRANT_SYNC
             )
         );