Ahh you have the insanely wonderful USB 3.0 issue that I tend to have. Here's one way that will help (hopefully) without a reboot:
Try this code in the terminal next time it happens:
There are issues with USB 3.0 on all kinds of distributions of Linux. I have found very few distributions of Linux that didn't have USB 3.0 issues in the past six months.
Anyway, that should do it. If not, please let me know. If it does help, then don't forget to click the little "helpful" button