I have a WP7 application that I run successfully on both WP7 and WP8 devices. In the app I download audio files using the `BackgroundFileTransfer` service and store the files to the `shared/transfers` folder. I then create `AudioTrack`s by giving a URI to the downloaded file locations.

```cs
        Uri episodeLocation;
        try
        {
            using (IsolatedStorageFile iso = IsolatedStorageFile.GetUserStoreForApplication())
            {
                Debug.WriteLine(" *** Creating track, file exists: " + iso.FileExists("shared/transfers/song.mp3"));
            }
            episodeLocation = new Uri("shared/transfers/song.mp3", UriKind.Relative);
        } catch(Exception) {
            return null;
        }

        return new AudioTrack(episodeLocation,
                        "Track name",
                        "Album name",
                        "",
                        new Uri("/path/to/logo", UriKind.Relative));

```

**This works great on both Windows Phone 7 and Windows Phone 8 devices** - audio player is able to play the track just fine. The debug output prints `True` as the result for the test if file exists. 

I've now converted the application in Visual Studio 2012 to be a Windows Phone 8 application. If I now run the application in Windows Phone 8, I get a `System.IO.FileNotFoundException` external exception from the player. Also in the converted version the debug output prints `True` when checking if the file exists. 

**I only converted the app from a WP7 to WP8 app** and I cannot refer to files in `shared/transfers` any more.

Why?

What's the proper way to do this? 

I already tried referring to the files by using the URI `isostore:/shared/transfers/song.mp3` but that didn't seem to have an effect.