though this is an old post. I had the same problems. I found out, that I had two "speakers" activated still. What windows (10) calls speakers is merely the output. since the ux2 replaces the soundcard there is no need for that to be active no matter what hardware one has. It was offline before. Maybe for some reason it got activated againg. I had my ux2 operating as the standard outpout while the other still had a green , active, status, whatever it exactly means. I deactivated the realtek one’s via the sound menu and the problem ceased to exist....!