I don't normally post to forums, but after experiencing issues with my UX2 with Windows 8 I found in the archived forums many other people were having the same problem (as recently as last month) with similar hardware. I was experiencing random audio dropouts on my PC. The audio would stop completely throughout all applications. The only way I could find to get it back was to restart my PC. I know it is not a hardware issue as I have a dual boot PC which runs both Windows 7 and windows 8. The UX2 always has always performed perfectly on Windows 7.
Here is the solution which appears to have fixed the issue on my PC. I was experiencing the problem multiple times daily since installing windows 8, but haven't had it reoccur since I found this setting about a week ago. I've been pulling my hair out for months and was right on the edge of uninstalling Windows 8, but now it seems to be working great. I'm hoping this post can help others enjoy their line6 devices again.
1. open power options.
2. click "change plan settings" for the plan you are currently using
3. Click "change advanced power settings"
4. Under USB settings -->USB selective suspend setting --> setting, change to disabled
(I have noticed the setting has changed itself back, but the problem hasn't reoccurred so maybe there's a bug in windows 8 in the power options. Maybe if yours is disabled by default, you could try enabling it)
Sorry to make this post so long, but since the forums have been archived I couldn't reply directly in the thread where the problem was first mentioned. I hope this is a permanent solution and helps everyone. If it does maybe someone could shout me a copy of Podfarm2.5 Platinum...just kidding