It is pickey I agree. I am using a 32gb USB 3.0. Not at that compter now, but I think it was kingston. I know that KB also says not usb 3.0
Only thing I know to do is try a different usb brand/stick
found it. This is whhat I got
http://www.amazon.com/gp/product/B005039I32/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
But I bought it 5/12/2012 so they may have changed?