It's worrying if you see the message “USB Device Not Recognised” when you plug in a hard drive or USB flash drive full of your precious files. But while there's a chance it is broken, it's also possible that you can get it working by delving into Windows' deeper settings. 

Various problems can cause the error message, from faulty USB ports or software drivers to corrupt partitions or even a dead USB drive. Read on and we’ll explain how to figure out what’s gone wrong.

How to fix an unrecognized USB drive

Try a different USB port or PC

A quick fix is to plug your drive into a different USB port. For example, try a USB port on the back of your PC rather than the front. This is because the rear ports are usually directly connected to the motherboard.

This also eliminates any USB hubs from the equation, as these can cause problems.

How to fix an unrecognized USB drive

If none of these methods work, try a different PC or laptop. If the drive is recognised, there’s a problem with the computer rather than the drive. But if it doesn’t show up on the other PC either, you've confirmed it’s a problem with the drive itself.

Does it appear in Disk Management?

If you suspect Windows is at fault, Disk Management is the place to go first.

Launch it by searching for Disk Management in the Start menu and clicking on the ‘Create and format hard disk partitions’ result. Alternatively, hit Windows key and R together and enter diskmgmt.msc into the box, then press Enter.

How to fix an unrecognized USB drive - Disk Management

A list of drives will appear as in the image above. You should be able to identify your USB drive by its capacity, or the fact it’s labelled as ‘Removable’. Some USB hard drives may not be shown as removable, however.

If you can see your drive here, but not in Windows Explorer (File Explorer in later versions of Windows), there are a couple of things you can do. First, check the partition status. If it isn’t showing as 'Healthy', along with a drive letter, this is why you can’t see the files. Skip to the next section if it's showing as Healthy but there's no drive letter.

You can try using a free tool such as TestDisk to fix the partition table. If it works, you should regain access to the drive and files.

If not, try PhotoRec  which looks at the data on the drive even if the partitions are corrupt.

If none of this works, or you’re not bothered about recovering the data on the drive, you may be able to right-click on the drive in Disk Management and format the drive so Windows can access it again. A wizard will guide you through the process.

If you can see that the drive is unallocated space, it means the partitions have been deleted. File recovery software might be able to help claw back deleted files.

How do I give it a drive letter?

If the drive has a primary partitions and is reported as 'Healthy', it might simply be missing a drive letter. To assign a drive letter right-click on the partition and choose Change Drive Letter and Paths, then add a drive letter. Be sure to choose one that isn’t used for any other drives.

How to fix an unrecognized USB drive - Drive letter

Don’t forget - as we said above - you can try plugging the drive into a second PC and looking to see if it appears in Disk Management to rule out bad USB ports.

Check Device Manager

If the drive doesn't appear in Disk Management, there may be a hardware or software issue. So the next place to check is Device Manager. Press the Windows key and R together and enter devmgmt.msc into the box, then press Enter. Alternatively, type dev man in the Start menu search box and it should appear in the results.

How to fix an unrecognized USB drive - Device manager

Expand the Disk drives section and look for any devices with a yellow triangle and black exclamation mark over its icon. If you see one, you have a driver problem. Right-click on the device and choose Properties and read the error message in the Device status box. If the solution isn’t obvious, try searching the internet for any error codes to see what they mean.

You can try updating the driver, too. Click the Driver tab and you might be able to roll back to a recent System Restore point or download the latest driver from the drive manufacturer’s website.

How to fix an unrecognized USB drive - Device manager

You can also try the Update Driver… button to see if Windows can locate a better driver, or use the Roll Back Driver button if it isn’t greyed out.

As a last resort, try the Uninstall button to uninstall the driver, then click OK and choose Scan for hardware changes in the Action menu.

Also look under the Universal Serial Bus controllers section within Device Manager, as there could be a driver problem for one of your computer’s USB controllers, which could cause an ‘unrecognised drive’ message.

How to fix an unrecognized USB drive - Device manager

It can be tricky to track down the correct driver, but if you know your motherboard make and model or the make and model of your laptop, you might be able to locate, download and install the latest drivers.

One last thing to try - as suggested by one of the comments below - is to change the write caching setting. Right-click on your drive in the Disk drives section of Device Manager and choose Properties. 

Click on the Policies tab and click the Better Performance radio button. This allows Windows to write files to the drive later on when it's convenient, but it means you'll have to Eject the drive manually in Windows instead of just removing the drive from the USB port. So don't leave it set to Better performance - this is just a test to try and get the drive working.

How to fix USB drive not recognised

Click OK and Device Manager should refresh the list. Your drive might now show up in Windows Explorer, but you can try ejecting it, and plugging it back in as well.

It's still not working!

If your USB drive still isn’t recognised after doing all the above, there’s a high chance it has failed and – unfortunately – will need to be replaced.