After updating to Windows 8.1 Update 1, my wife installed a USB flash drive that previously gave her no problems, and now wouldn’t show as a drive in Explorer. I got the same error on my (also updated) computer.

A notification was in the system tray to view devices, which showed the flash drive icon. Right-clicking that and choosing Troubleshoot suggested removing the device and reinserting. Some web searching said the same thing—which was almost right. However, the driver wasn’t being fully removed, so kept getting used again, resulting in the same error.

Instead, the driver needs to be completely removed. To do this:

1. Plug in the flash drive.
2. Open Device Manager.
3. Find the bad device.
4. Right-click and choose Uninstall.
5. When prompted, check Delete the software for this device.
6. Unplug the drive, then plug it back in.
7. The drive should now be available.