Hi there, I have the same problem with my hd500x. My UX2 gave some other problems (lags, clicking noise etc). I've managed to fix that by using this driver: http://www.asio4all.org/
Maybe that will help you. Good luck!
ps: There seems to be a serious problem with line 6 drivers and certain drivers in computers. I'm just curious, what computer do you use? Mine is a lenovo laptop and I've read about multiple conflicts there.