A USB flash drive inserted into one USB port stopped being fully recognized by the computer. A second later, it would work perfectly fine in the port right next to the non-working one. The jump drive was not working by the following terms:
It did not show up as a drive under My Computer.
The disk management tool under the Microsoft Management Console did not show any file system on the drive although it did see the drive.
The “safely eject hardware” icon pops up with the insertion of the USB key.
I tried:
Formatting the drive while it was unplugged in the “bad” port.
Uninstalling the drivers associated with the drive.
Successfully tested different USB drives in the “bad” port without a problem.
Finally found success with a work-around mentioned in the following linked Microsoft Knowledge Base article (always be cautious when using the Registry Editor). Open the Registry Editor (Start, Run: regedit) and navigate to HKEY_LOCAL_MACHINESystemCurrentControlSetServicesUSB
If the DisableSelectiveSuspend key doesn’t exist, like it didn’t for me, create it by right-clicking on the right pane. Then create a DWORD value inside the USB key and set the value to 1.
Immediately, my USB key started working in both front ports like normal. It seems the one port and one drive associated each other in a powered-off state and this gave it a kick start.
http://support.microsoft.com/kb/817900
This fixed the particular problem I was experiencing where the computer suddenly stopped recognizing the USB jump drive in one particular port. You’ll want to double-check that there is a free letter for the USB to obtain and that it doesn’t overlap with a mapped drive. For that reason, I recommend mapped drives take later letters (M-Z). You might also try removing U3 software if your jump drive is unfortunately stuck with it or formatting the drive in case something is wrong with the file system. Be sure to back up the data on your drive before tinkering with it.