If you are running ScanDisk or another disk utility and encounter bad clusters, sectors, or allocation units, we recommend you back up your data and then format the hard drive.

  • How to back up your computer.
  • How to erase my hard drive and start over?

Encounter errors

If bad sectors or missing allocation units are encountered while the hard drive is being formatted, your hard drive is bad. In this instance, we suggest that the hard drive be replaced.

  • Computer hard drive buying tips.
  • How to install a hard drive or SSD.

No errors encountered

If no errors are encountered during the format process, it is likely corrupt software was running on the drive and causing the errors. Running the format and restore process should have resolved these errors and this issue should be fixed.

Can bad sectors be repaired?

No. If a software utility such as ScanDisk detects bad sectors, they’re marked as bad and will be skipped when information is written to the hard drive. Any data found on those bad sectors is considered lost.

  • Hard drive help and support.
  • See the bad sectors, cluster, sector, and allocation unit definitions for further information.