Hololens - Optical SeeThrough & TargetInvocationException

Hello,

I'm currently developing some application on the Hololens. Imported both the Mixed Reality Toolkit and the Vuforia Sample Project. Here I tried to set it up like in the Tutorial, but in the VuforiaConfiguration of the ARCamera the Digital Eyeviewer doesn't know the option "Optical SeeThrough", the Vuforia Sample sets it to "Digital Eyewear"?

Well, the Unity Project still does recognize the Camera and seems to work fine. But when I build the Project and run it with Visual Studio on my device I get en error:

Exception in callback: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object.    at Vuforia.DatabaseLoadARController.LoadDatasets()    at Vuforia.VuforiaARController.Start()    --- End of inner exception stack trace ---    at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)    at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)    at System.Delegate.DynamicInvokeImpl(Object[] args)    at Vuforia.DelegateHelper.InvokeDelegate(Delegate action, Object[] args)

Using: Unity 2017.3.0f3, Visual Studio 2017 (latest update), Real Hololense (not emulator!)

Thanks for any fast advise!