CheckExistsAsync does not finish

Mar 17 at 8:46 PM

I have the following function that does never return.
I'm using it with xamarin. PCL Version: 1.0.2
I've tried it with a Windows PC and Windows Phone Emulator.
On the Windows Phone Emulator the call does once return after my PC was restarted.
Read and Write Files works well as far as I can see.
    private bool existsData(string name)
        string myFolderName = "Shuttle";
        IFolder rootFolder = FileSystem.Current.LocalStorage;

        IFolder folder = rootFolder.CreateFolderAsync(myFolderName, CreationCollisionOption.OpenIfExists).Result;

        ExistenceCheckResult x = folder.CheckExistsAsync(name).Result;
        return x == ExistenceCheckResult.FileExists;

Any Ideas what the Problem could be?