Windows 10?
Did you check in: Settings (gear on start menu) -> Privacy (Location, Camera) -> Camera
Under Choose which apps can access your camera is Driver4VR listed, and set to ON?
One of the “awesome” updates I received for Windows 10 broke 3d Scan, a MS app, for using the Kinect with anything, so I check it for everything now. The camera privacy can break a lot of different things when you’re not expecting it.