Windows is nasty with USB. There are bugs where speeds crawl and the only way to fix it is to sacrifice several endangered chickens while chanting black magic in ancient Egyptian as you... etc. etc.
Try deleting the device in the device manager then rebooting. Idiotic? Yes. Does it work? Kind of. But you can try the chicken thing too. It probably works better.
That's kinda how I feel also. That's why I never really liked USB, fromt he beginning days, for anything really serious. yeah, I love it for peripherals, thumbdrives...but for any serious work like backing up, syncing reliably, migrating drives, etc. I always try to stay away from it. When esata came out, i really wanted it to replace usb for everything, like make it extinct. I love esata. now we have thunderbolt, but nothing is really taking advantage of it. Like, i want thunderbolt enclosures, thunderbolt thumbdrives, etc. And I don't know what all the specific issues are, so that's all I can say , is what i want.
so whatever. I want things like a thunderbolt external plug on a tower, where I plug in a thunderbolt hub, connect like 5 external drives to it, and move files around to each of them with >100 MB/s speeds. things like that. That would be progress that i'd consider to be very exciting.