How to Fix a Corrupted USB or External Hard Drive

•
Ankit Kumar
Data RecoveryStorageFix

The Problem

You plug in a USB stick or external drive and Windows offers to format it, or reports that the file or directory is corrupted. The file system index is damaged; the data underneath is very often still intact.

Do not click Format. Not yet, and not "just to see". Formatting rewrites the file system and makes recovery substantially harder.

The Order That Matters

This is the part most guides get wrong. If the files matter more than the drive:

Recover the data first, repair the drive second.

chkdsk writes to the disk. On a healthy volume with minor index damage it fixes things neatly. On a badly damaged or failing drive it can move data into FOUND.000 folders as numbered .chk fragments, or make things worse. If the contents are irreplaceable, image or recover before running any repair tool.

Why It Happens

  • Unplugging without ejecting, while a write was still buffered.
  • Power loss during a write.
  • A failing USB port, a poor cable, or an underpowered hub.
  • The drive itself beginning to fail.

Step 1: Rule Out the Simple Things

  1. Try a different USB port, directly on the motherboard at the rear of a desktop.
  2. Try a different cable—especially with 2.5-inch portable drives, where a marginal cable causes exactly this.
  3. Try the drive on another computer.
  4. For a desktop external drive, confirm its power adapter is connected and working.
  5. Listen. Clicking, beeping, or a repetitive spin-up-and-stop means mechanical failure—stop immediately and go to the last section.

Step 2: Check What Windows Sees

Right-click Start → Disk Management.

| What it shows | Meaning | Next | |---|---|---| | Healthy with a drive letter, but Explorer errors | File system damage | Step 3 | | RAW | The file system is unreadable | Step 4 — chkdsk will not help | | Unallocated | Partition table lost | Step 4 | | No drive letter | Simple assignment problem | Right-click → Change Drive Letter and Paths → Add | | Not listed at all | Hardware, cable, or power | Step 1, then the last section |

Step 3: Repair the File System With chkdsk

Only when Disk Management shows a healthy file system, and only when you accept the small risk described above.

Open Terminal (Admin) and run a read-only scan first:

chkdsk X: /scan

Replace X: with the actual drive letter. This reports problems without changing anything.

If it reports errors and you are ready to repair:

chkdsk X: /f /r /x
  • /f fixes file system errors
  • /r locates bad sectors and recovers readable data
  • /x dismounts the volume first

On a large drive /r can take many hours. Let it finish; interrupting it mid-write is worse than not starting.

Afterwards, check for a FOUND.000 folder in the root of the drive. Recovered fragments land there as .chk files, and some can be renamed back to their original extension.

Step 4: RAW or Unallocated — Recover, Do Not Repair

When the file system is gone, chkdsk reports "The type of the file system is RAW. CHKDSK is not available for RAW drives." That is expected, not a further fault.

The data is still physically present. What is missing is the map. Recovery software scans the raw sectors for file signatures and reconstructs what it finds.

  1. Never write anything to the affected drive, including installing the recovery tool.
  2. Install the tool on your system drive, and set the recovery destination to a third location with enough free space.
  3. Run a quick scan first, then a deep signature scan if needed.
  4. Preview files before recovering, and recover everything you care about in one pass.

Technician's solution: when standard tools fail on RAW or accidentally formatted external drives, RecoverPro carves files from raw sectors and writes them safely to a different drive.

For a general walkthrough: how to recover deleted files.

Step 5: Rebuild the Drive Afterwards

Once your data is safe, you can decide whether to keep using the drive.

  1. Check its health first: check SSD or hard drive health. Reallocated or pending sector counts above zero mean retire it.
  2. If it is healthy, format it properly: Disk Management → right-click → Format → NTFS for Windows-only use, or exFAT for use with Macs, cameras, and TVs.
  3. Full method: partition and format a drive in Windows 11.

When to Stop and Get Help

Stop using the drive and consider a professional data-recovery service if:

  • It clicks, beeps, or grinds.
  • It disappears from Disk Management partway through a scan.
  • It spins up and immediately down again.
  • The data is genuinely irreplaceable and no software has read it.

Repeated power cycles on a mechanically failing drive destroy more data each time. A lab can read platters that software never will—it is expensive, but running recovery software in a loop first often removes that option.

Prevention

  • Use Safely Remove Hardware before unplugging, every time.
  • Prefer exFAT over FAT32 for large drives, and NTFS for Windows-only use.
  • Keep a second copy of anything on an external drive—portable drives are the least reliable storage most people own: set up automatic backups.

Getting "The file or directory is corrupted and unreadable"? That is error 0x80070570 and it has its own diagnosis path: fix error 0x80070570.

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