Symptoms
- CHKDSK reports 'bad sectors' after a scan
- Certain files repeatedly become corrupted or unreadable
- Windows occasionally freezes when accessing specific files or folders
- Drive is several years old or has had a rough physical history
Likely causes
- CommonNormal wear on an aging mechanical hard driveAll hard drives eventually develop some bad sectors with age.
- PossiblePhysical shock or vibration damageA drop or bump, even a small one, can create new bad sectors.
- PossibleA failing drive with a growing number of bad sectorsA handful is common with age; a rapidly growing count signals real trouble.
What to do
- Back up all important data from the drive before doing anything else, since running repairs on a failing drive carries some risk.
- Run 'chkdsk /r' from an elevated Command Prompt, which scans for and marks bad sectors as unusable so Windows avoids them.
- Let the scan run fully; on a large or heavily damaged drive this can take several hours.
- After it finishes, check if the same files still have problems or if performance has improved.
- Run the scan again after a few weeks to see if the bad sector count is growing, which would indicate ongoing failure.
- If the count keeps increasing or grows quickly, plan to replace the drive rather than keep repairing it.
When to call a pro
If the bad sector count keeps climbing on repeat scans, back up everything and replace the drive rather than continuing to run repairs.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.