I was having the same problem. I found the trick was to uninstall ALL the Line 6 Monkey stuff and drivers and then just download the driver direct. It really frustrated me as I have a UX1 I was looking to sell and just wanted to double check it was in working order. It was so bad it jammed the boot up of my MAC. Just another reason I don't like Line 6 gear, it's always a little questionable about how well the stuff will work.