How to fix a USB flash drive that is corrupted and unreadable?

USB flash drives, also known as thumb drives or USB sticks, are small portable data storage devices that connect to computers via a USB port. They contain flash memory chips that store and retain data even when not powered on. While USB drives are generally reliable, they can become corrupted or unreadable over time for various reasons:

Filesystem corruption – The filesystem that organizes and provides access to data on the drive can get corrupted from improper ejection, suddenly powering off, or physical damage. This renders files inaccessible.[1]

Bad sectors – Portions of the flash storage can fail and develop bad sectors that prevent data from being read or written properly.

Degradation – The electrical charge stored in the flash memory cells can degrade over years of usage or if left unused for long periods.[2] This leads to data errors.

Physical damage – Drops, dirt, liquids, or extremes of heat can physically damage the USB and its components, making the data unreadable.

Software issues – Problems with the operating system, drivers, or other software can sometimes make a USB drive not work properly.

When a USB drive stops working or can’t be accessed anymore, the data may still be recoverable through various troubleshooting steps as outlined in this guide.



Determine If the Drive is Really Corrupted

The first step is to plug the USB drive into your computer’s USB port and see if it shows up and can be accessed normally. Try viewing it in Windows Explorer or File Explorer (for Mac) to see if the drive’s contents can be viewed.

If the drive does not show up at all or you get an error saying the drive needs to be formatted, it’s likely corrupted. Try plugging it into different USB ports on your computer or connecting it to another computer to verify the drive itself is having issues.

You can also check Disk Management in Windows (Disk Utility on Mac) to see if the USB drive shows up there. If you see the drive but cannot access files, it points to corruption. Checking Disk Management also allows you to see if the drive has the proper file system format.

If the USB drive fails to show up properly across multiple computers and in Disk Management, it’s safe to assume the drive is corrupted or damaged in some way.

Try Using Disk Utilities

One of the first things to try when a USB flash drive becomes corrupted or unreadable is using built-in disk repair tools like CHKDSK on Windows or Disk Utility on Mac. These tools can scan the drive and fix common errors related to file system structures or directories.

On Windows, you can access CHKDSK by right-clicking the corrupted drive in File Explorer, selecting Properties > Tools > Check. Check both boxes to ‘Automatically fix file system errors’ and ‘Scan for and attempt recovery of bad sectors’. Then click Start to begin the scan and repair process. CHKDSK will attempt to fix drive errors and make it readable again.[1]

On Mac, open Disk Utility and select the corrupted USB drive on the left. Click First Aid at the top, then click Run to begin scanning and repairing errors. The First Aid verification and repair process may take some time, but afterwards the drive should hopefully be fixed and accessible again if it’s a simple file system issue.[2]

Disk utilities like CHKDSK and First Aid can resolve many minor corruption problems with USB flash drives quickly and easily. They should be the first troubleshooting step tried before moving on to more advanced USB repair methods.

Format the Drive

One of the first troubleshooting steps to try when a USB flash drive becomes corrupted or unreadable is formatting it. Formatting will completely erase all data on the drive and restructure the file system. This can potentially fix errors that are preventing the drive from being accessed properly.

For general purpose USB flash drives, the two main file system options are FAT32 and exFAT. According to PCMag, FAT32 is compatible with both Windows and Mac, but has a maximum individual file size of 4GB. ExFAT removes this limitation while still having wide compatibility (PCMag). Many recommend exFAT as the best format for USB drives as it doesn’t have the overhead of NTFS but is faster and more efficient than FAT32.

To format a USB drive on Windows, use the File Explorer to right-click on the drive, select Format, and then choose exFAT or FAT32. On Mac, open Disk Utility, select the drive, click Erase, and select a format. Be sure to back up any important files first, as formatting will erase everything on the drive.

Clean the Drive Contacts

Sometimes corruption issues can be caused by dirty contacts between the USB flash drive and computer USB port. Try cleaning the contacts on both the drive and port using rubbing alcohol on a cotton swab.

Gently rub the cotton swab dampened with a small amount of rubbing alcohol on the metal contacts of the USB flash drive. Be sure not to get any moisture inside the drive housing. Allow it to fully dry before reinserting.

Next, use a new cotton swab dampened with rubbing alcohol to gently clean inside the USB port you are trying to use. Allow it to fully dry as well.

Cleaning both surfaces will help create a solid connection between the contacts and may resolve any connectivity issues leading to the corruption.

If the drive still isn’t being recognized properly after cleaning, try switching to a different USB port or cable.

Try a Different USB Port or Cable

One of the easiest things to try is swapping out the USB port or cable you’re using. A damaged USB port or faulty cable can prevent your computer from properly communicating with the flash drive.

First, try plugging the flash drive into another USB port on your computer. If it still isn’t recognized, try using a different USB cable altogether. Standard USB cables can become loose or frayed over time, reducing connectivity. According to research by GadgetMates, the average lifespan of a USB cable with regular use is 1-3 years before signs of damage appear.

If the drive functions properly with a new USB port or cable, then the original one is likely at fault. Replacing a damaged USB cable is quicker and simpler than fixing the drive itself. Investing in a high durability USB cable, storing it properly, and avoiding strain can significantly extend its lifespan.

Check for Physical Damage

One of the most common reasons USB flash drives become corrupted or unreadable is physical damage to the drive or connector. Carefully inspect the drive casing and USB connector for any signs of damage:

  • Cracks, dents, or broken pieces in the metal or plastic housing
  • Bent, damaged, or missing pins in the USB connector
  • Detached or loose components inside the casing

Even minor damage to the physical drive can prevent proper contact between the USB connector and port, resulting in connectivity issues. If the damage is severe enough, it can cause short circuits and permanent corruption of data on the flash memory chips inside.

Sometimes the damage may not be visible on the surface but can still affect connections internally. Plugging the drive into multiple USB ports and cables can help determine if the issue stems from physical damage versus a problem with the specific port or cable.

If physical damage is confirmed, options become limited. But it may still be possible to recover data using specialized data recovery services designed for physically damaged drives before replacing the defective USB flash drive.

Use Data Recovery Software

Data recovery software can often extract data from corrupted or damaged drives. Utilities like Recuva or Stellar Data Recovery will scan the flash drive and attempt to restore lost files. Follow these steps:

  1. Download and install the data recovery software.
  2. Connect the flash drive to the computer.
  3. Launch the software and select the flash drive to scan.
  4. Choose a thorough scan option to detect all recoverable files.
  5. Preview found files and select those to restore.
  6. Choose a folder to save the recovered data.

Many data recovery tools offer free trial versions allowing you to see if your files can be retrieved before purchasing. Recovery success depends on the extent of drive corruption. But quality software can often extract data even from severely damaged drives.

Send to a Data Recovery Service

If the data you lost is extremely important or valuable, using a professional data recovery service may be worth the cost. Reputable data recovery companies have specialized tools and expertise to retrieve data from drives that are inaccessible or severely damaged. Here are some things to know about using professional recovery services:

  • Costs range widely, but expect to pay a minimum fee of $100-200 just for evaluation. The actual recovery can run $300-1000+ depending on the service level.
  • The more complex the job, the more it will cost. Logical recoveries of deleted files are cheaper than repairs of physical damage.
  • Choose a reputable recovery company and get an estimate upfront. Read reviews and make sure they have experience with your type of media.
  • Recovery success is not guaranteed. But professionals may have the best chance if DIY options failed.

Data recovery services are often the last resort when all other options have been exhausted. While expensive, they can potentially recover irreplaceable data from drives with severe logical or physical damage. Contact a specialized data recovery company for an evaluation if the lost data is extremely valuable or important.[1]

When All Else Fails, Replace It

If after trying all the troubleshooting steps the USB flash drive is still not working, it may be time to replace it. Most flash drives have a limited lifespan and can fail after extended use over time.

According to one source, under ideal conditions, data should remain preserved on a high-quality USB flash drive for up to 10 years. However, flash drives will eventually reach their write/erase cycle limit which can cause corruption and failure [1]. Heavy or frequent usage will shorten the lifespan.

If the flash drive is several years old, has had significant use, or has been exposed to harsh conditions, it may simply be beyond repair. Purchasing a new flash drive is recommended if you have exhausted all other troubleshooting options.

When buying a replacement, look for a quality drive with high storage capacity and durability. Avoid cheap low-quality drives which tend to have shorter lifespans. Also consider a drive designed for long-term archival storage if you need to preserve data for many years.