People report Windows 8.1 drops their drive and so forth. I don’t know all the specifics about all of those probelms but maybe there’s hope for a quick fix for at least some people who come to this forum for help.
Windows update for Windows 8.1 contains a “rollup”, and, as you know, by “rollup” they mean a bundle of updates that comes in one package: patches, fixes, etc.
The rollup is described in KB2911106. The USB 3.0 storage device problem addressed is in KB2914219.
If auto update is on, you’re getting it according to whatever schedule you have set. For me, I set up to manually check and download. Just noticed what was in there.
It’s an optional Windows 8.1 update if you do manual selections like I do.