diff --git a/doomsday/engine/api/dd_share.h b/doomsday/engine/api/dd_share.h
index 2fd1fdf8bf..def17d9bab 100644
--- a/doomsday/engine/api/dd_share.h
+++ b/doomsday/engine/api/dd_share.h
@@ -1727,7 +1727,7 @@ typedef struct serverinfo_s {
     char            gameConfig[40];
     char            map[20];
     char            clientNames[128];
-    unsigned int    wadNumber;
+    unsigned int    loadedFilesCRC;
     char            iwad[32];   ///< Obsolete.
     char            pwads[128];
     int             data[3];
diff --git a/doomsday/engine/include/filesys/fs_main.h b/doomsday/engine/include/filesys/fs_main.h
index 59ee332bfd..d0490c0beb 100644
--- a/doomsday/engine/include/filesys/fs_main.h
+++ b/doomsday/engine/include/filesys/fs_main.h
@@ -272,6 +272,11 @@ namespace de
         /// Register the console commands, variables, etc..., of this module.
         static void consoleRegister();
 
+        /**
+         * @post No more WADs will be loaded in startup mode.
+         */
+        void endStartup();
+
         /**
          * @param name      Unique symbolic name of this namespace. Must be at least
          *                  @c Namespace::min_name_length characters long.
@@ -279,12 +284,6 @@ namespace de
          */
         Namespace& createNamespace(String name, Namespace::Flags flags = 0);
 
-        /**
-         * Reset all the namespaces, returning them to an empty state and clearing
-         * any @ref ExtraPaths which have been registered since construction.
-         */
-        void resetAllNamespaces();
-
         /**
          * Lookup a Namespace by symbolic name.
          *
@@ -293,13 +292,14 @@ namespace de
          */
         Namespace* namespaceByName(String name);
 
-        /// Returns the namespaces for efficient traversal.
-        Namespaces const& namespaces();
-
         /**
-         * @post No more WADs will be loaded in startup mode.
+         * Reset all the namespaces, returning them to an empty state and clearing
+         * any @ref ExtraPaths which have been registered since construction.
          */
-        void endStartup();
+        void resetAllNamespaces();
+
+        /// Returns the namespaces for efficient traversal.
+        Namespaces const& namespaces();
 
         /**
          * Add a new path mapping from source to destination in the vfs.
@@ -309,10 +309,8 @@ namespace de
 
         /**
          * Clears all virtual path mappings.
-         *
-         * @return  This instance.
          */
-        FS1& clearPathMappings();
+        void clearPathMappings();
 
         /**
          * Add a new lump mapping so that @a lumpName becomes visible at @a destination.
@@ -324,13 +322,12 @@ namespace de
          *
          * @return  This instance.
          */
-        FS1& clearPathLumpMappings();
+        void clearPathLumpMappings();
 
         /**
-         * Reset known fileId records so that the next time checkFileId() is called for
-         * a filepath, it will pass.
+         * @return  @c true if a file exists at @a path which can be opened for reading.
          */
-        void resetFileIds();
+        bool accessFile(Uri const& path);
 
         /**
          * Maintains a list of identifiers already seen.
@@ -341,26 +338,28 @@ namespace de
         bool checkFileId(Uri const& path);
 
         /**
-         * @return  @c true if a file exists at @a path which can be opened for reading.
+         * Reset known fileId records so that the next time checkFileId() is called for
+         * a filepath, it will pass.
          */
-        bool accessFile(Uri const& path);
+        void resetFileIds();
 
         /**
          * Indexes @a file (which must have been opened with this file system) into
          * this file system and adds it to the list of loaded files.
          *
          * @param file      The file to index. Assumed to have not yet been indexed!
-         *
-         * @return  This instance.
          */
-        FS1& index(File1& file);
+        void index(File1& file);
 
         /**
          * Removes a file from any lump indexes.
          *
          * @param file  File to remove from the index.
          */
-        FS1& deindex(File1& file);
+        void deindex(File1& file);
+
+        /// Clear all references to this file.
+        void releaseFile(File1& file);
 
         /**
          * Lookup a lump by name.
@@ -425,9 +424,6 @@ namespace de
          */
         FileHandle& openLump(File1& lump);
 
-        /// Clear all references to this file.
-        void releaseFile(File1& file);
-
         /**
          * Find a single file.
          *
@@ -529,11 +525,6 @@ namespace de
          */
         void printDirectory(String path);
 
-        /**
-         * Calculate a CRC for the loaded file list.
-         */
-        uint loadedFilesCRC();
-
         /**
          * Try to open the specified WAD archive into the auxiliary lump index.
          *
@@ -546,11 +537,16 @@ namespace de
          */
         void closeAuxiliaryPrimaryIndex();
 
+        /**
+         * Calculate a CRC for the loaded file list.
+         */
+        uint loadedFilesCRC();
+
         /**
          * Unload all files loaded after startup.
          * @return  Number of files unloaded.
          */
-        FS1& unloadAllNonStartupFiles(int* numUnloaded = 0);
+        int unloadAllNonStartupFiles();
 
     private:
         struct Instance;
@@ -599,7 +595,7 @@ void F_Shutdown(void);
 
 void F_EndStartup(void);
 
-void F_UnloadAllNonStartupFiles(int* numUnloaded);
+int F_UnloadAllNonStartupFiles();
 
 void F_AddVirtualDirectoryMapping(char const* nativeSourcePath, char const* nativeDestinationPath);
 
@@ -663,7 +659,7 @@ void F_UnlockLump(struct file1_s* file, int lumpIdx);
  */
 void F_ComposePWADFileList(char* outBuf, size_t outBufSize, const char* delimiter);
 
-uint F_CRCNumber(void);
+uint F_LoadedFilesCRC(void);
 
 lumpnum_t F_OpenAuxiliary2(char const* nativePath, size_t baseOffset);
 lumpnum_t F_OpenAuxiliary(char const* nativePath/*, baseOffset = 0 */);
diff --git a/doomsday/engine/src/filesys/fs_main.cpp b/doomsday/engine/src/filesys/fs_main.cpp
index 381ee5328d..577c6be56d 100644
--- a/doomsday/engine/src/filesys/fs_main.cpp
+++ b/doomsday/engine/src/filesys/fs_main.cpp
@@ -460,7 +460,13 @@ FS1::~FS1()
 FS1::Namespace& FS1::createNamespace(String name, Namespace::Flags flags)
 {
     DENG_ASSERT(name.length() >= Namespace::min_name_length);
-    Namespace* fnamespace = new Namespace(name, flags);
+
+    // Ensure this is a unique name.
+    Namespace* fnamespace = namespaceByName(name);
+    if(fnamespace) return *fnamespace;
+
+    // Create a new namespace.
+    fnamespace = new Namespace(name, flags);
     d->namespaces.insert(name.toLower(), fnamespace);
     return *fnamespace;
 }
@@ -518,7 +524,7 @@ static FS1::FileList::iterator findListFileByPath(FS1::FileList& list, String pa
     return i;
 }
 
-FS1& FS1::index(de::File1& file)
+void FS1::index(de::File1& file)
 {
 #ifdef DENG_DEBUG
     // Ensure this hasn't yet been indexed.
@@ -560,14 +566,12 @@ FS1& FS1::index(de::File1& file)
     // Add a handle to the loaded files list.
     FileHandle* loadedFilesHndl = FileHandleBuilder::fromFile(file);
     d->loadedFiles.push_back(loadedFilesHndl); loadedFilesHndl->setList(reinterpret_cast<struct filelist_s*>(&d->loadedFiles));
-
-    return *this;
 }
 
-FS1& FS1::deindex(de::File1& file)
+void FS1::deindex(de::File1& file)
 {
     FileList::iterator found = findListFile(d->loadedFiles, file);
-    if(found == d->loadedFiles.end()) return *this; // Most peculiar..
+    if(found == d->loadedFiles.end()) return; // Most peculiar..
 
     QByteArray path = file.composePath().toUtf8();
     d->releaseFileId(path.constData());
@@ -579,8 +583,6 @@ FS1& FS1::deindex(de::File1& file)
 
     d->loadedFiles.erase(found);
     delete *found;
-
-    return *this;
 }
 
 de::File1& FS1::find(de::Uri const& search)
@@ -701,7 +703,7 @@ static void printFileList(FS1::FileList& list)
 }
 #endif
 
-FS1& FS1::unloadAllNonStartupFiles(int* retNumUnloaded)
+int FS1::unloadAllNonStartupFiles()
 {
 #if _DEBUG
     // List all open files with their identifiers.
@@ -734,8 +736,7 @@ FS1& FS1::unloadAllNonStartupFiles(int* retNumUnloaded)
     }
 #endif
 
-    if(retNumUnloaded) *retNumUnloaded = numUnloadedFiles;
-    return *this;
+    return numUnloadedFiles;
 }
 
 bool FS1::checkFileId(de::Uri const& path)
@@ -1260,10 +1261,9 @@ void FS1::mapPathToLump(String lumpName, String destination)
     LOG_VERBOSE("Path \"%s\" now mapped to lump \"%s\"") << NativePath(ldm->first).pretty() << ldm->second;
 }
 
-FS1& FS1::clearPathLumpMappings()
+void FS1::clearPathLumpMappings()
 {
     d->lumpMappings.clear();
-    return *this;
 }
 
 /// @return  @c true iff the mapping matched the path.
@@ -1313,10 +1313,9 @@ void FS1::mapPath(String source, String destination)
         << NativePath(pm->second).pretty() << NativePath(pm->first).pretty();
 }
 
-FS1& FS1::clearPathMappings()
+void FS1::clearPathMappings()
 {
     d->pathMappings.clear();
-    return *this;
 }
 
 void FS1::printDirectory(String path)
@@ -1636,9 +1635,9 @@ void F_EndStartup(void)
     App_FileSystem()->endStartup();
 }
 
-void F_UnloadAllNonStartupFiles(int* numUnloaded)
+int F_UnloadAllNonStartupFiles(void)
 {
-    App_FileSystem()->unloadAllNonStartupFiles(numUnloaded);
+    return App_FileSystem()->unloadAllNonStartupFiles();
 }
 
 void F_AddVirtualDirectoryMapping(char const* nativeSourcePath, char const* nativeDestinationPath)
@@ -2027,7 +2026,7 @@ void F_ComposePWADFileList(char* outBuf, size_t outBufSize, char const* delimite
     strncpy(outBuf, strUtf8.constData(), outBufSize);
 }
 
-uint F_CRCNumber(void)
+uint F_LoadedFilesCRC(void)
 {
     return App_FileSystem()->loadedFilesCRC();
 }
diff --git a/doomsday/engine/src/network/net_main.c b/doomsday/engine/src/network/net_main.c
index 21d1a4c8a1..ef4af669a9 100644
--- a/doomsday/engine/src/network/net_main.c
+++ b/doomsday/engine/src/network/net_main.c
@@ -888,7 +888,7 @@ void Net_PrintServerInfo(int index, serverinfo_t *info)
                    info->canJoin ? ' ' : '*', info->version, info->plugin,
                    info->address, info->port);
         Con_Printf("    %s p:%ims %-40s\n", info->map, info->ping, info->description);
-        Con_Printf("    %s (crc:%x) %s\n", info->gameIdentityKey, info->wadNumber, info->gameConfig);
+        Con_Printf("    %s (crc:%x) %s\n", info->gameIdentityKey, info->loadedFilesCRC, info->gameConfig);
 
         // Optional: PWADs in use.
         if(info->pwads[0])
diff --git a/doomsday/engine/src/network/ui_mpi.c b/doomsday/engine/src/network/ui_mpi.c
index e588ae7a78..f2f0d3d783 100644
--- a/doomsday/engine/src/network/ui_mpi.c
+++ b/doomsday/engine/src/network/ui_mpi.c
@@ -334,7 +334,7 @@ void MPIUpdateServerInfo(ui_object_t *ob)
 
     sprintf(warningString,
             "This server is using %x, " "but you have %x. "
-            "Errors may occur during game play.", info.wadNumber, myCrc);
+            "Errors may occur during game play.", info.loadedFilesCRC, myCrc);
 
     // Show IWAD warning?
     if(!(lst_found.count >= 1 && lst_found.selection >= 0 &&
@@ -469,7 +469,7 @@ void MPIUpdateServerList(void)
                 memset(&info, 0, sizeof(info));
                 N_GetHostInfo(i, &info);
                 MPIFormatServerInfo(lstit_found[i].text, &info);
-                lstit_found[i].data = info.wadNumber;
+                lstit_found[i].data = info.loadedFilesCRC;
                 lstit_found[i].data2 = i;
             }
             lst_found.count = num;
@@ -495,7 +495,7 @@ void MPIUpdateServerList(void)
             }
 
             MPIFormatServerInfo(lstit_found[k].text, &info);
-            lstit_found[k].data = info.wadNumber;
+            lstit_found[k].data = info.loadedFilesCRC;
             // Connection will be formed using this index.
             lstit_found[k].data2 = i;
             k++;
@@ -656,7 +656,7 @@ void DD_NetSetup(int serverMode)
         UI_FlagGroup(ob_client, 4, UIF_HIDDEN, searchMode == SEARCH_MASTER);
         lst_found.selection = -1;
         lst_found.count = 0;
-        myCrc = F_CRCNumber();
+        myCrc = F_LoadedFilesCRC();
         UI_FlagGroup(ob_client, 5, UIF_DISABLED, true); // warnings
         UI_FlagGroup(ob_client, UIG_CONNECT, UIF_DISABLED, true);
         MPIUpdateServerList();
diff --git a/doomsday/engine/src/server/sv_main.c b/doomsday/engine/src/server/sv_main.c
index 8c07ce2742..8062343d8f 100644
--- a/doomsday/engine/src/server/sv_main.c
+++ b/doomsday/engine/src/server/sv_main.c
@@ -118,7 +118,7 @@ void Sv_GetInfo(serverinfo_t* info)
     F_ComposePWADFileList(info->pwads, sizeof(info->pwads), ";");
 
     // This should be a CRC number that describes all the loaded data.
-    info->wadNumber = F_CRCNumber();
+    info->loadedFilesCRC = F_LoadedFilesCRC();
 }
 
 /**
@@ -136,7 +136,7 @@ size_t Sv_InfoToString(serverinfo_t* info, ddstring_t* msg)
     Str_Appendf(msg, "mode:%s\n", info->gameIdentityKey);
     Str_Appendf(msg, "setup:%s\n", info->gameConfig);
     Str_Appendf(msg, "iwad:%s\n", info->iwad);
-    Str_Appendf(msg, "wcrc:%i\n", info->wadNumber);
+    Str_Appendf(msg, "wcrc:%i\n", info->loadedFilesCRC);
     Str_Appendf(msg, "pwads:%s\n", info->pwads);
     Str_Appendf(msg, "map:%s\n", info->map);
     Str_Appendf(msg, "nump:%i\n", info->numPlayers);
@@ -247,7 +247,7 @@ boolean Sv_StringToInfo(const char *valuePair, serverinfo_t *info)
     }
     else if(!strcmp(label, "wcrc"))
     {
-        info->wadNumber = strtol(value, 0, 0);
+        info->loadedFilesCRC = strtol(value, 0, 0);
     }
     else if(!strcmp(label, "pwads"))
     {