How to Fix Bad Sectors on a Hard Drive: What Works and What Doesn't

Bad sectors are areas on a hard drive that cannot be reliably read or written. They come in two types with very different implications: logical bad sectors (fixable with software) and physical bad sectors (permanent hardware damage).

Part 1. Logical vs Physical Bad Sectors

⚠️ Important: Physical bad sectors cannot be repaired by any software. CHKDSK marks them as unusable (so the OS doesn't write to them again), but the physical damage remains. A growing count of physical bad sectors indicates the drive is deteriorating — replace it before it fails completely.

Part 2. Fix Logical Bad Sectors With CHKDSK

CHKDSK maps bad sectors and attempts to recover readable data from them:

chkdsk C: /f /r

• /f — fixes file system errors
• /r — locates bad sectors and recovers readable data, marking the sector as unusable

💡 Tip: CHKDSK /r can take several hours on large drives with many bad sectors. Run it overnight. If it appears stuck at a percentage for more than an hour, it is working through a cluster of particularly difficult sectors — do not interrupt it.

Part 3. Check SMART Data for Physical Degradation

Use CrystalDiskInfo to check these critical SMART attributes:

💡 Tip: If Reallocated Sectors Count was 0 yesterday and is now > 0, physical damage has begun. The drive is drawing from its spare sector reserve. When the reserve is exhausted, sectors simply fail with no replacement. This is the time to replace the drive.

Part 4. When to Stop Fixing and Start Recovering

🗣️ r/techsupport advice on bad sectors: "CHKDSK will map bad sectors and mark them unusable, which can make the drive temporarily usable again. But bad sectors tend to spread. A drive that develops bad sectors will develop more. Treat it as a warning and replace it."

🗣️ r/datarecovery guidance: "Recover your data first. Then run CHKDSK. Then replace the drive. Don't CHKDSK first — it can overwrite recoverable data in sectors adjacent to the bad ones during its repair process."

Part 5. Recover Files From a Drive With Bad Sectors With Ritridata

Ritridata can scan drives with bad sectors and recover files from accessible regions — reading around the bad sectors rather than through them.

Step 1 — Select the drive with bad sectors from the list

Step 2 — Run a scan — reads accessible sectors, skips bad areas

Step 3 — Recover files to a healthy external drive immediately

FAQ

Can bad sectors be repaired permanently? Logical bad sectors can be repaired by CHKDSK (the sector's data is corrected or the sector is mapped out). Physical bad sectors are permanently damaged — CHKDSK marks them as unusable, but the physical damage remains. There is no software that repairs the physical magnetic surface.

How many bad sectors is too many? Any physical bad sector is concerning — it indicates the drive has started physically degrading. Zero is normal. Even a small number of physical bad sectors warrants immediate backup and planning for drive replacement.

Will CHKDSK fix bad sectors? CHKDSK can fix logical bad sectors and map physical bad sectors as unusable. It cannot repair the physical surface damage that causes hard bad sectors. After CHKDSK marks them unusable, the OS won't write to those areas — but new bad sectors can continue to develop.

Can a drive with bad sectors still be used? Yes, with caution — after CHKDSK maps bad sectors, the drive can continue to function for months. But a drive with physical bad sectors is at elevated risk of further failure. Use it only with a complete backup in place and plan to replace it soon.

References

• CrystalDiskInfo — SMART Monitoring
• Microsoft — CHKDSK
• r/techsupport — Bad Sectors CHKDSK
• r/datarecovery — Recover Before CHKDSK
• r/hardware — SMART Bad Sectors