Published 2022-12-10 by TechNet New England
When Windows does not recognize a USB device, you may see "USB Device Not Recognized," no notification at all, or the device appears in Device Manager with a yellow warning triangle. ## Fix 1: Try a Different Port Unplug the device and plug it into a different USB port on the computer. Try both USB-A and USB-C ports if available. Avoid USB hubs for troubleshooting. ## Fix 2: Try a Different Cable If the device uses a removable cable (like a phone or external drive), try a different cable. Cables degrade over time, especially at the connectors. ## Fix 3: Restart Unplug the device, restart the computer, then plug the device back in after Windows fully loads. ## Fix 4: Check Device Manager 1. Right-click **Start > Device Manager**. 2. Look for **Unknown device** or a device with a yellow triangle under **Universal Serial Bus controllers** or **Other devices**. 3. Right-click the device > **Update driver > Search automatically**. 4. If that does not work, right-click > **Uninstall device**, then unplug and replug the USB device. Windows will reinstall the driver. ## Fix 5: Uninstall USB Controllers 1. In Device Manager, expand **Universal Serial Bus controllers**. 2. Right-click each **USB Root Hub** and select **Uninstall device**. 3. Restart the computer. 4. Windows will reinstall the USB controllers automatically. ## Fix 6: Check Power Management Windows sometimes turns off USB ports to save power. 1. In Device Manager, expand **Universal Serial Bus controllers**. 2. Right-click each **USB Root Hub** > **Properties > Power Management**. 3. Uncheck **Allow the computer to turn off this device to save power**. 4. Click **OK**. ## Fix 7: Check the Device on Another Computer Plug the USB device into a different computer. If it does not work there either, the device itself may be faulty. ## USB Drive Specific If a USB flash drive or external hard drive is not recognized: 1. Open **Disk Management** (right-click Start > Disk Management). 2. Look for the USB drive. It may appear without a drive letter. 3. Right-click the drive partition and select **Change Drive Letter and Paths > Add** to assign a letter. 4. If it shows as "Unallocated" or "RAW," the drive may need to be formatted (which erases all data). Contact IT before formatting if the data is important. ## When to Contact IT If no USB devices work on the computer, the USB ports may have a hardware issue or a Group Policy may be restricting USB access. On managed computers, USB storage devices are sometimes blocked by security policy. Contact your IT provider.