USB issues are often tricky to narrow down, and rarely have anything to do with the product specifically but rather is a quirk of the usb communication protocols. In my experience, the issues are often related to power downs or sleep modes which can happen on both the dac or computer side, which causes a blip in the usb connection and freezes the dac.
The procedure that almost always works for is to turn off the dac, unplug the cable, turn the dac back on and replug the usb cable. Inconvenient, but it should work because it resets everything and starts a brand new connection rather than try to resume an old one.
Sometimes a powered usb hub works (though depending on the hub, sometimes you'll have to reinstall the drivers)
Or the simplest is to just leave everything on all the time.