Contacted the support about 2 years ago regarding my secondhand Pod XT. I would be doing whatever on the computer, playing guitar, games, videos etc and suddenly the sound would disappear. Trying to change to another soundcard didn't work or anything regarding sound for that matter because somehow the sound was 'locked' or I presume, stuck in a loop... The support told me it was a hardware problem, since we'd tried everything else, and suggested I sent it to repair. I didn't though, I just kept going, only had to restart the computer when it happened so I didn't feel like spending money on something I'd pay 50 euro for. But now I have bought a new HD 500X and it is fine and all, BUT suddenly the sound disappeared... Hardware malfunction? Hardly. I've been checking some old forum post and I'm not the only one with this problem. So my suggestion to Line6 is that you gather as much information you can on this problem and fix it. I would start by checking your codes for handling the USB...