diff --git a/CampusAppWP8/CampusAppWP8/CampusAppWP8.csproj b/CampusAppWP8/CampusAppWP8/CampusAppWP8.csproj
index a4942f33..dec8a31a 100644
--- a/CampusAppWP8/CampusAppWP8/CampusAppWP8.csproj
+++ b/CampusAppWP8/CampusAppWP8/CampusAppWP8.csproj
@@ -441,7 +441,7 @@
   <ItemGroup>
     <Reference Include="Microsoft.Phone.Controls, Version=8.0.0.0, Culture=neutral, PublicKeyToken=24eec0d8c86cda1e, processorArchitecture=MSIL" />
     <Reference Include="Microsoft.Phone.Controls.Toolkit">
-      <HintPath>..\packages\WPtoolkit.4.2012.10.30\lib\wp8\Microsoft.Phone.Controls.Toolkit.dll</HintPath>
+      <HintPath>..\packages\WPToolkit.4.2013.06.11\lib\wp8\Microsoft.Phone.Controls.Toolkit.dll</HintPath>
     </Reference>
   </ItemGroup>
   <ItemGroup>
diff --git a/CampusAppWP8/CampusAppWP8/Model/MainModel.cs b/CampusAppWP8/CampusAppWP8/Model/MainModel.cs
index 9e5f85af..ba793fda 100644
--- a/CampusAppWP8/CampusAppWP8/Model/MainModel.cs
+++ b/CampusAppWP8/CampusAppWP8/Model/MainModel.cs
@@ -116,6 +116,11 @@ namespace CampusAppWP8
         /// </summary>
         public delegate void OnSaved();
 
+        /// <summary>
+        /// Delegate of the OnFailed(File/Web) callback function.
+        /// </summary>
+        public delegate void OnFailed();
+
         /// <summary>
         /// Delegate of the IsModelUpToDate callback function.
         /// </summary>
@@ -151,6 +156,22 @@ namespace CampusAppWP8
         /// </summary>
         public event OnSaved onSaved = null;
 
+        /// <summary>
+        /// Callback pointer, called after failed file loading.
+        /// </summary>
+        public event OnFailed onFailedFile = null;
+
+        /// <summary>
+        /// Callback pointer, called after failed web loading.
+        /// </summary>
+        public event OnFailed onFailedWeb = null;
+
+        /// <summary>
+        /// Callback pointer, called after failed file or web loading, if there
+        /// is no specialized onFailed callback set.
+        /// </summary>
+        public event OnFailed onFailed = null;
+
         /// <summary>
         /// Callback pointer, for checking if file is up to date at loading.
         /// </summary>
@@ -294,7 +315,18 @@ namespace CampusAppWP8
                 {
                     string data = this.file.ReadFile();
 
-                    if (data != null && !data.Equals(string.Empty))
+                    if (data == null)
+                    {
+                        if (this.onFailedFile != null)
+                        {
+                            this.onFailedFile();
+                        }
+                        else if (this.onFailed != null)
+                        {
+                            this.onFailed();
+                        }
+                    }
+                    else if (!data.Equals(string.Empty))
                     {
                         this.DeserializeModel(Encoding.UTF8.GetBytes(data));
                     }
@@ -486,6 +518,15 @@ namespace CampusAppWP8
             Exception downloadError = e.Error;
             if (downloadError != null)
             {
+                if (this.onFailedWeb != null)
+                {
+                    this.onFailedWeb();
+                }
+                else if (this.onFailed != null)
+                {
+                    this.onFailed();
+                }
+
                 return;
             }
 
diff --git a/CampusAppWP8/CampusAppWP8/Utility/File.cs b/CampusAppWP8/CampusAppWP8/Utility/File.cs
index 6b6349a5..ae66a2e5 100644
--- a/CampusAppWP8/CampusAppWP8/Utility/File.cs
+++ b/CampusAppWP8/CampusAppWP8/Utility/File.cs
@@ -220,20 +220,48 @@ namespace CampusAppWP8.Utility
         /// <param name="data">data array</param>
         private async void WriteAsync(byte[] data)
         {
+            Logger.LogMsg("writeasync file: " + this.filename);
+            StorageFile file = null;
+            Stream s = null;
+
+            // try opening the file
+            while (file == null)
+            {
+                try
+                {
+                    file = await File.LocalFolder.CreateFileAsync(this.filename, CreationCollisionOption.ReplaceExisting);
+                }
+                catch (Exception)
+                {
+                    System.Threading.Thread.Sleep(10);
+                }
+            }
+
+            // try to get a stream on the file
+            while (s == null)
+            {
+                try
+                {
+                    s = await file.OpenStreamForWriteAsync();
+                }
+                catch (Exception)
+                {
+                    System.Threading.Thread.Sleep(10);
+                }
+            }
+
+            // writing data
             try
             {
-                var file = await File.LocalFolder.CreateFileAsync(this.filename, CreationCollisionOption.ReplaceExisting);
-
-                using (var s = await file.OpenStreamForWriteAsync())
-                {
-                    await s.WriteAsync(data, 0, data.Length);
-                }
+                await s.WriteAsync(data, 0, data.Length);
+                await s.FlushAsync();
             }
             catch (Exception e)
             {
-                // log write Error
                 Logger.LogException(e);
             }
+
+            s.Dispose();
         }
     }
 }
\ No newline at end of file
diff --git a/CampusAppWP8/CampusAppWP8/Utility/Logger.cs b/CampusAppWP8/CampusAppWP8/Utility/Logger.cs
index 69fa2898..6b8d3d33 100644
--- a/CampusAppWP8/CampusAppWP8/Utility/Logger.cs
+++ b/CampusAppWP8/CampusAppWP8/Utility/Logger.cs
@@ -22,5 +22,14 @@ namespace CampusAppWP8.Utility
         {
             Console.WriteLine(exception);
         }
+
+        /// <summary>
+        /// Log a message.
+        /// </summary>
+        /// <param name="msg">to be logged message</param>
+        public static void LogMsg(string msg)
+        {
+            Console.WriteLine(msg);
+        }
     }
 }
diff --git a/CampusAppWP8/CampusAppWP8/packages.config b/CampusAppWP8/CampusAppWP8/packages.config
index a6c4d07d..f3d7e2f0 100644
--- a/CampusAppWP8/CampusAppWP8/packages.config
+++ b/CampusAppWP8/CampusAppWP8/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="WPtoolkit" version="4.2012.10.30" targetFramework="wp80" />
+  <package id="WPToolkit" version="4.2013.06.11" targetFramework="wp80" />
 </packages>
\ No newline at end of file