Windows Phone 8.1 throws a FileLoadException on startup

I'm currently building a Windows Phone 8.1 App (WinRT). I can build it in Debug Mode in Visual Studio 2013 without any problems. It is also runs in the emulator and on a real device. But when I build the app in Release mode it crashes instantly on both the emulator and the device.

In the Debug Output windows of Visual Studio I can see that a FileLoadException is thrown on startup. This means:

The exception that is thrown when a managed assembly is found but cannot be loaded.

https://msdn.microsoft.com/de-de/library/system.io.fileloadexception%28v=vs.110%29.aspx

Unfortunately I can not see which assembly causes the problem! Is there any means to make the information visible?

A first chance exception of type 'System.IO.FileLoadException' occurred in MarketIQ.exe
A first chance exception of type 'System.IO.FileLoadException' occurred in mscorlib.ni.dll
'MarketIQ.exe' (CoreCLR: .): Loaded 'C:\windows\system32\en-US\mscorlib.debug.resources.dll'. Module was built without symbols.
A first chance exception of type 'System.ArgumentException' occurred in mscorlib.ni.dll
A first chance exception of type 'System.ArgumentException' occurred in mscorlib.ni.dll
'MarketIQ.exe' (CoreCLR: .): Loaded 'C:\Data\SharedData\PhoneTools\AppxLayouts\c53a5ef4-9f4f-4a1d-a5f4-2e73b5806daeVS.Release_AnyCPU.oprins\Log.Model.Client.DLL'. Cannot find or open the PDB file.
The program '[3020] MarketIQ.exe' has exited with code -1073741189 (0xc000027b).

The problem was device dependent. The app now runs smoothly after a factory reset.