I can't offer much. When I see that I reboot and use the desktop's rear USB ports. Sorry but there is a lot of discussions about this so I'll give you what's worked for me.
Since a while, when I connect a USB stick, appears a window with the following message : This device can perform faster if you connect it to a Hi-Speed 2.0 port and I end up at the crawling speed of a USB 1.0.
Any idea ?