diff --git a/MediaBrowser.Controller/Entities/Folder.cs b/MediaBrowser.Controller/Entities/Folder.cs
index 457a0b3ab..949b333d4 100644
--- a/MediaBrowser.Controller/Entities/Folder.cs
+++ b/MediaBrowser.Controller/Entities/Folder.cs
@@ -1293,33 +1293,41 @@ namespace MediaBrowser.Controller.Entities
 
         public IList<BaseItem> GetRecursiveChildren(Func<BaseItem, bool> filter)
         {
-            var list = new List<BaseItem>();
+            var result = new Dictionary<Guid, BaseItem>();
 
-            AddChildrenToList(list, true, filter);
+            AddChildrenToList(result, true, true, filter);
 
-            return list;
+            return result.Values.ToList();
         }
 
         /// <summary>
         /// Adds the children to list.
         /// </summary>
-        /// <param name="list">The list.</param>
-        /// <param name="recursive">if set to <c>true</c> [recursive].</param>
-        /// <param name="filter">The filter.</param>
-        private void AddChildrenToList(List<BaseItem> list, bool recursive, Func<BaseItem, bool> filter)
+        private void AddChildrenToList(Dictionary<Guid,BaseItem> result, bool includeLinkedChildren, bool recursive, Func<BaseItem, bool> filter)
         {
             foreach (var child in Children)
             {
                 if (filter == null || filter(child))
                 {
-                    list.Add(child);
+                    result[child.Id] = child;
                 }
 
                 if (recursive && child.IsFolder)
                 {
                     var folder = (Folder)child;
 
-                    folder.AddChildrenToList(list, true, filter);
+                    folder.AddChildrenToList(result, includeLinkedChildren, true, filter);
+                }
+            }
+
+            if (includeLinkedChildren)
+            {
+                foreach (var child in GetLinkedChildren())
+                {
+                    if (filter == null || filter(child))
+                    {
+                        result[child.Id] = child;
+                    }
                 }
             }
         }
diff --git a/MediaBrowser.Providers/Manager/MetadataService.cs b/MediaBrowser.Providers/Manager/MetadataService.cs
index 218127ab9..a0c6bd889 100644
--- a/MediaBrowser.Providers/Manager/MetadataService.cs
+++ b/MediaBrowser.Providers/Manager/MetadataService.cs
@@ -421,7 +421,8 @@ namespace MediaBrowser.Providers.Manager
                 var folder = item as Folder;
                 if (folder != null && folder.SupportsCumulativeRunTimeTicks)
                 {
-                    var ticks = folder.GetRecursiveChildren(i => !i.IsFolder).Select(i => i.RunTimeTicks ?? 0).Sum();
+                    var items = folder.GetRecursiveChildren(i => !i.IsFolder).ToList();
+                    var ticks = items.Select(i => i.RunTimeTicks ?? 0).Sum();
 
                     if (!folder.RunTimeTicks.HasValue || folder.RunTimeTicks.Value != ticks)
                     {
@@ -443,9 +444,10 @@ namespace MediaBrowser.Providers.Manager
                 var folder = item as Folder;
                 if (folder != null && folder.SupportsDateLastMediaAdded)
                 {
-                    var date = folder.GetRecursiveChildren(i => !i.IsFolder).Select(i => i.DateCreated).Max();
+                    var items = folder.GetRecursiveChildren(i => !i.IsFolder).Select(i => i.DateCreated).ToList();
+                    var date = items.Count == 0 ? (DateTime?)null : items.Max();
 
-                    if (!folder.DateLastMediaAdded.HasValue || folder.DateLastMediaAdded.Value != date)
+                    if ((!folder.DateLastMediaAdded.HasValue && date.HasValue) || folder.DateLastMediaAdded != date)
                     {
                         folder.DateLastMediaAdded = date;
                         updateType = ItemUpdateType.MetadataEdit;
diff --git a/MediaBrowser.Providers/Movies/MovieUpdatesPrescanTask.cs b/MediaBrowser.Providers/Movies/MovieUpdatesPrescanTask.cs
index f7f0fd6cc..70c155ad5 100644
--- a/MediaBrowser.Providers/Movies/MovieUpdatesPrescanTask.cs
+++ b/MediaBrowser.Providers/Movies/MovieUpdatesPrescanTask.cs
@@ -176,9 +176,13 @@ namespace MediaBrowser.Providers.Movies
             var numComplete = 0;
 
             // Gather all movies into a lookup by tmdb id
-            var allMovies = _libraryManager.RootFolder
-                .GetRecursiveChildren(i => i is Movie && !string.IsNullOrEmpty(i.GetProviderId(MetadataProviders.Tmdb)))
-                .ToLookup(i => i.GetProviderId(MetadataProviders.Tmdb));
+            var allMovies = _libraryManager.GetItemList(new Controller.Entities.InternalItemsQuery
+            {
+                IncludeItemTypes = new[] {typeof (Movie).Name},
+                Recursive = true
+
+            }).Where(i => !string.IsNullOrEmpty(i.GetProviderId(MetadataProviders.Tmdb)))
+            .ToLookup(i => i.GetProviderId(MetadataProviders.Tmdb));
 
             foreach (var id in list)
             {
diff --git a/MediaBrowser.Server.Implementations/FileOrganization/EpisodeFileOrganizer.cs b/MediaBrowser.Server.Implementations/FileOrganization/EpisodeFileOrganizer.cs
index 270f01b2b..f402a0a33 100644
--- a/MediaBrowser.Server.Implementations/FileOrganization/EpisodeFileOrganizer.cs
+++ b/MediaBrowser.Server.Implementations/FileOrganization/EpisodeFileOrganizer.cs
@@ -116,7 +116,7 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
                         premiereDate,
                         options,
                         overwriteExisting,
-						false,
+                        false,
                         result,
                         cancellationToken).ConfigureAwait(false);
                 }
@@ -202,7 +202,7 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
                 null,
                 options,
                 true,
-				request.RememberCorrection,
+                request.RememberCorrection,
                 result,
                 cancellationToken).ConfigureAwait(false);
 
@@ -219,7 +219,7 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
             DateTime? premiereDate,
             AutoOrganizeOptions options,
             bool overwriteExisting,
-			bool rememberCorrection,
+            bool rememberCorrection,
             FileOrganizationResult result,
             CancellationToken cancellationToken)
         {
@@ -242,7 +242,7 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
                 premiereDate,
                 options,
                 overwriteExisting,
-				rememberCorrection,
+                rememberCorrection,
                 result,
                 cancellationToken);
         }
@@ -255,7 +255,7 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
             DateTime? premiereDate,
             AutoOrganizeOptions options,
             bool overwriteExisting,
-			bool rememberCorrection,
+            bool rememberCorrection,
             FileOrganizationResult result,
             CancellationToken cancellationToken)
         {
@@ -536,7 +536,11 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
             result.ExtractedName = nameWithoutYear;
             result.ExtractedYear = yearInName;
 
-            var series = _libraryManager.RootFolder.GetRecursiveChildren(i => i is Series)
+            var series = _libraryManager.GetItemList(new Controller.Entities.InternalItemsQuery
+            {
+                IncludeItemTypes = new[] { typeof(Series).Name },
+                Recursive = true
+            })
                 .Cast<Series>()
                 .Select(i => NameUtils.GetMatchScore(nameWithoutYear, yearInName, i))
                 .Where(i => i.Item2 > 0)
@@ -550,10 +554,12 @@ namespace MediaBrowser.Server.Implementations.FileOrganization
 
                 if (info != null)
                 {
-                    series = _libraryManager.RootFolder
-                        .GetRecursiveChildren(i => i is Series)
-                        .Cast<Series>()
-                        .FirstOrDefault(i => string.Equals(i.Name, info.ItemName, StringComparison.OrdinalIgnoreCase));
+                    series = _libraryManager.GetItemList(new Controller.Entities.InternalItemsQuery
+                    {
+                        IncludeItemTypes = new[] { typeof(Series).Name },
+                        Recursive = true
+                    }).Cast<Series>()
+                    .FirstOrDefault(i => string.Equals(i.Name, info.ItemName, StringComparison.OrdinalIgnoreCase));
                 }
             }
 
diff --git a/MediaBrowser.Server.Implementations/Library/UserDataManager.cs b/MediaBrowser.Server.Implementations/Library/UserDataManager.cs
index d3aad20f5..0fabbf54a 100644
--- a/MediaBrowser.Server.Implementations/Library/UserDataManager.cs
+++ b/MediaBrowser.Server.Implementations/Library/UserDataManager.cs
@@ -22,7 +22,7 @@ namespace MediaBrowser.Server.Implementations.Library
     {
         public event EventHandler<UserDataSaveEventArgs> UserDataSaved;
 
-        private readonly ConcurrentDictionary<string, UserItemData> _userData = new ConcurrentDictionary<string, UserItemData>();
+        private readonly Dictionary<string, UserItemData> _userData = new Dictionary<string, UserItemData>(StringComparer.OrdinalIgnoreCase);
 
         private readonly ILogger _logger;
         private readonly IServerConfigurationManager _config;
@@ -66,8 +66,10 @@ namespace MediaBrowser.Server.Implementations.Library
 
                     var newValue = userData;
 
-                    // Once it succeeds, put it into the dictionary to make it available to everyone else
-                    _userData.AddOrUpdate(GetCacheKey(userId, key), newValue, delegate { return newValue; });
+                    lock (_userData)
+                    {
+                        _userData[GetCacheKey(userId, key)] = newValue;
+                    }
                 }
                 catch (Exception ex)
                 {
@@ -154,13 +156,33 @@ namespace MediaBrowser.Server.Implementations.Library
                 throw new ArgumentNullException("key");
             }
 
-            return _userData.GetOrAdd(GetCacheKey(userId, key), keyName => GetUserDataFromRepository(userId, key));
+            lock (_userData)
+            {
+                var cacheKey = GetCacheKey(userId, key);
+                UserItemData value;
+                if (_userData.TryGetValue(cacheKey, out value))
+                {
+                    return value;
+                }
+
+                value = GetUserDataFromRepository(userId, key);
+                _userData[cacheKey] = value;
+                return value;
+            }
         }
 
         private UserItemData GetUserDataFromRepository(Guid userId, string key)
         {
             var data = Repository.GetUserData(userId, key);
 
+            if (data == null)
+            {
+                data = new UserItemData
+                {
+                    UserId = userId,
+                    Key = key
+                };
+            }
             return data;
         }
 
diff --git a/MediaBrowser.Server.Implementations/Persistence/SqliteItemRepository.cs b/MediaBrowser.Server.Implementations/Persistence/SqliteItemRepository.cs
index 180bd3547..20cc7f82a 100644
--- a/MediaBrowser.Server.Implementations/Persistence/SqliteItemRepository.cs
+++ b/MediaBrowser.Server.Implementations/Persistence/SqliteItemRepository.cs
@@ -2056,6 +2056,10 @@ namespace MediaBrowser.Server.Implementations.Persistence
         {
             var whereClauses = new List<string>();
 
+            if (EnableJoinUserData(query))
+            {
+                whereClauses.Add("UserId=@UserId");
+            }
             if (query.IsCurrentSchema.HasValue)
             {
                 if (query.IsCurrentSchema.Value)
diff --git a/MediaBrowser.Server.Implementations/Persistence/SqliteUserDataRepository.cs b/MediaBrowser.Server.Implementations/Persistence/SqliteUserDataRepository.cs
index 8c521d88a..7f3b32e06 100644
--- a/MediaBrowser.Server.Implementations/Persistence/SqliteUserDataRepository.cs
+++ b/MediaBrowser.Server.Implementations/Persistence/SqliteUserDataRepository.cs
@@ -296,11 +296,7 @@ namespace MediaBrowser.Server.Implementations.Persistence
                     }
                 }
 
-                return new UserItemData
-                {
-                    UserId = userId,
-                    Key = key
-                };
+                return null;
             }
         }
 
diff --git a/MediaBrowser.Server.Implementations/ScheduledTasks/ChapterImagesTask.cs b/MediaBrowser.Server.Implementations/ScheduledTasks/ChapterImagesTask.cs
index e50de7bac..607a043a6 100644
--- a/MediaBrowser.Server.Implementations/ScheduledTasks/ChapterImagesTask.cs
+++ b/MediaBrowser.Server.Implementations/ScheduledTasks/ChapterImagesTask.cs
@@ -12,6 +12,7 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using CommonIO;
+using MediaBrowser.Model.Entities;
 
 namespace MediaBrowser.Server.Implementations.ScheduledTasks
 {
@@ -85,8 +86,13 @@ namespace MediaBrowser.Server.Implementations.ScheduledTasks
         /// <returns>Task.</returns>
         public async Task Execute(CancellationToken cancellationToken, IProgress<double> progress)
         {
-            var videos = _libraryManager.RootFolder.GetRecursiveChildren(i => i is Video)
-                .Cast<Video>()
+            var videos = _libraryManager.GetItemList(new InternalItemsQuery
+            {
+                MediaTypes = new[] { MediaType.Video },
+                IsFolder = false,
+                Recursive = true
+            })
+                .OfType<Video>()
                 .ToList();
 
             var numComplete = 0;
@@ -97,7 +103,7 @@ namespace MediaBrowser.Server.Implementations.ScheduledTasks
 
             try
             {
-				previouslyFailedImages = _fileSystem.ReadAllText(failHistoryPath)
+                previouslyFailedImages = _fileSystem.ReadAllText(failHistoryPath)
                     .Split(new[] { '|' }, StringSplitOptions.RemoveEmptyEntries)
                     .ToList();
             }