USB Unknown Device Drive Issue, Not Working, Recognized or Connected Error After Upgrading and Installing Vista SP1

After installing Windows Vista SP1, or more specifically, one of the prerequisite update for the service pack, KB938371, that just been re-released early April after Microsoft claimed already fixed an endless reboot loop issue, USB device may stop working. Such USB-based devices involve broad categories, such as mice (mouse), keyboard, external or portable hard disk, USB flash drive, card reader and etc.

In slight different to another USB problem where symptom is Vista unable to find driver for USB device automatically, the USB connected device not working issue cannot be solved by simply removing and then reinstalling the drivers. When plug in an USB device, the USB device is either not detected, not recognized, or not connected. If Windows Vista tries to install the driver, the USB device is listed as “Unknown Device”, and no driver will be found to install the device, or drive installation fails. So the USB device cannot be used as Windows will always ask for driver.

Microsoft acknowledges the issue with USB device after installing KB938371 with statement that “We are aware of concerns that a recent Microsoft update may be causing problems with USB devices, according to TheRegister. We are investigating the matter, and at this time, do not have any information to share.” So there is no official fix from Microsoft yet, other than asking users to check for updated or latest drivers from manufacturer’s websites.

Although Microsoft hasn’t publish any resolution for USB not working issue after installing KB938271 or Windows Vista SP1 (which must also installed the affected prerequisite update), but TechNet forum users have manage to fix or resolve the issue with a workaround, which is reported caused by Human Interface Device in combination with update KB938371.

1. Go to Control Panel, then go to System and Maintenance, then go to System, and click on Device Manager.
2. In the Device Manager, expand the tree of Human Interface Devices (HID).
3. Update the driver for all Unknown Device.
4. Windows Vista won’t be able to retrieve any driver online, as expected. So when prompted for how to search for driver software, select Browse my computer for driver software.
5. Enter or browse to C:\Windows\winsxs as the driver location and press the Next button.
6. If the system pops up a dialog warning about unsigned driver, allow the driver installation to continue.
7. Windows Vista with SP1 will install the appropriate driver for the device, and the USB device should be able to work properly again.

Note: If the driver cannot be installed, try to boot into Safe Mode and repeat above steps again.