[Wilkesin]

I've noticed a couple of USB audio devices just are arent happy sharing a buss with anything else. I've also noticed that there doesnt seem to be any rhyme or reason to which USB ports share a buss necessarily.

Try moving which USB port you are connecting the interface to around and see what that does and be aware it may not make any sense which ports are sharing a buss in terms of their orientation vertically or horizontally on your machine.