Just want to say, that I have the same issues like others described here, the whole package (audio dissapears, restart problems, driver_power_state_failure etc), my OS is W8.1, Pod HD. Everything started with Line 6 installation, no problems ever before, no problems with other USB interfaces (tried steinberg, tried zoom g3).
Tried pretty much everything, nothing help. Submitted several tickets, got fast responses and different suggestions, unfortunately nothing helped so far.
I am close to give up and use other interface.