How to remove bad sectors from hard disk without formatting?

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How to remove bad sectors from hard disk without formatting

Disk bad sectors are problematic areas on your hard drive that no longer can store and retrieve data. Dealing with bad sectors is frustrating, but there are ways to remove bad sectors without having to reformat your entire drive and lose all your data.

What causes bad sectors?

Bad sectors are physical defects on the hard drive platter surface that prevent data from being read or written. There are several potential causes of bad sectors:

  • Physical damage – Scratches, dents, or other physical damage to the platter surface can cause bad sectors.
  • Manufacturing defects – Imperfections in the platters during the manufacturing process can lead to bad sectors developing over time.
  • Age and wear – As a hard drive ages and is used extensively, the platters can degrade and bad sectors form.
  • Overheating – Excessive heat from a failing fan or other issue can warp the platters and cause bad sectors.
  • Strong magnetic fields – Exposure to strong magnets can disrupt the magnetic properties of the platters leading to bad sectors.
  • Power surges – Surges during startup or from electrical storms can damage the controller board or platters.

Once bad sectors develop, they will not repair themselves or disappear. The damage is permanent and the sectors will continue to deteriorate until the drive completely fails.

Warning signs of bad sectors

How can you tell your hard disk is developing bad sectors? Here are some warning signs:

  • Unreadable data – You cannot access files or data stored in a bad sector. The files may appear corrupted or missing altogether.
  • Disk errors – Your operating system may display disk read/write error messages pointing to problems accessing specific sectors.
  • Performance issues – Programs may freeze or respond slowly as they struggle to access bad sectors.
  • Strange noises – Clicking, grinding or buzzing sounds may indicate the drive is having trouble reading sectors.
  • File system corruption – Bad sectors can corrupt file system tables leading to unusable drives.

If you suspect your drive has bad sectors, you can run diagnostics to identify the locations of bad sectors. This will allow you to quarantine them off so they do not cause further problems.

Checking for bad sectors in Windows

Windows operating systems have built-in tools to scan for bad sectors and attempt to repair them. Here are some methods to check for bad sectors in Windows:

Chkdsk

Chkdsk is a command line utility built into Windows that examines the file system and checks for problems such as bad sectors. To use it:

  1. Open the Command Prompt as administrator.
  2. Type “chkdsk C: /f” and press Enter to run it on your C drive. Replace C: with the letter of the drive you want to scan.
  3. Chkdsk will scan the drive and display any bad sector locations if found.
  4. Add the /r option to also locate and recover readable data from bad sectors.

SFC Scan

The System File Checker tool will scan system files for corruption and repair them. SFC can resolve bad sectors in system files:

  1. Open an admin Command Prompt.
  2. Type “sfc /scannow” and hit Enter to run an immediate full scan.
  3. SFC will replace corrupted system files caused by bad sectors from a backup cache.

Drive Properties

You can check for errors in the hard drive properties:

  1. Open Explorer and right-click on the hard drive.
  2. Select “Properties” and go to the Tools tab.
  3. Click “Check” under Error Checking.
  4. Check “Scan for and attempt recovery of bad sectors” to locate bad sectors.

Checking for bad sectors in Mac OS

Mac OS also includes utilities to verify disks and identify bad sectors:

Disk Utility First Aid

Disk Utility can check internal and external drives for errors:

  1. Open Disk Utility.
  2. Select the drive on the left sidebar.
  3. Click First Aid and select Run to begin scanning.
  4. First Aid will report if any bad sectors are found.

fsck in Terminal

The fsck command checks file system integrity:

  1. Open Terminal.
  2. Type “fsck -fy” and press Enter to scan your startup drive.
  3. Use “fsck -fy /dev/disk2” replacing disk2 with the drive you want to scan.
  4. fsck will output results of any bad sector detection.

Drive Information

You can also view basic drive health information:

  1. Go to  > About This Mac > Storage.
  2. Select your drive and click Information.
  3. Check S.M.A.R.T. Status for verification the drive is in good health.

Using third party tools

For more robust bad sector detection and repair, you can use third party utilities:

Hard Disk Sentinel

Hard Disk Sentinel is an advanced drive health monitoring program available for Windows, Mac and Linux. It offers extensive bad sector detection and repair features including:

  • Detailed disk scan results identifying all bad sectors.
  • SMART parameter analysis to predict drive failures.
  • Repair mode to repair damaged areas without data loss.
  • Hard Disk Healer to fix damaged surfaces and blocks.

HDD Regenerator

HDD Regenerator is designed specifically for bad sector repair in Windows. Key features include:

  • Scans drives for damaged sectors and predicts possible failures.
  • Reads data from damaged sectors and attempts full sector regeneration.
  • Repairs damage caused by bad sectors.
  • Monitors drive health via S.M.A.R.T parameters.

DiskDrill

DiskDrill includes protections against bad sectors on Mac and Windows drives:

  • SMART disk monitoring checks drive health statistics.
  • Prediction algorithms forecast possible bad sector issues.
  • Recovery Vault preserves backup metadata to reconstruct lost files.
  • Scans and repairs corrupted partitions.

Be sure to backup important data before running repairs since bad sectors may still result in data loss.

Removing bad sectors via low-level formatting

Low-level formatting reconfigures the hard disk platters and mapping. Unlike regular quick formatting, it wipes all data and resets sectors. This removes bad sectors but is highly risky:

  • Destructive – Low-level formatting erases all data. The drive is completely reset to factory state.
  • Lengthy process – It can take several hours to complete on larger drives vs quick formatting.
  • Not full proof – Physical damage may be beyond repair so bad sectors could remain or gradually reappear.

Due to the data risks, low-level formatting should only be used as a last resort if other bad sector removal options have failed. Consult a data recovery professional first.

Steps to low-level format a drive in Windows

If fully aware of data loss risks, here are the steps to low-level format in Windows:

  1. Backup all data from the drive first.
  2. Connect the hard drive directly via SATA/IDE cable, not through USB.
  3. Use the Windows DiskPart tool:
    1. Open admin Command Prompt.
    2. Type “diskpart” and press Enter.
    3. Type “list disk” to identify the disk number for the target drive.
    4. Type “select disk X” replacing X with your disk number.
    5. Type “clean” and press Enter to start the low-level format.
  4. Wait several hours for the process to complete.

Steps to low-level format a drive on Mac

To low-level format on Mac:

  1. Backup all data first.
  2. Connect the hard drive directly via SATA/IDE cable if external.
  3. Boot into macOS Recovery Mode by holding Command + R on startup.
  4. Launch Disk Utility from the Utilities menu.
  5. Select the drive and click Erase at the top.
  6. Set Format to “Mac OS Extended (Journaled).”
  7. Select Scheme to “GUID Partition Map.”
  8. Check “Overrite Data With Zeros” to wipe all data.
  9. Click Erase to low-level format the drive.

Conclusion

Bad sectors can happen to any drive and lead to performance issues or data loss if left unchecked. While low-level formatting is an aggressive fix, less destructive options like Chkdsk, Disk Utility, and third party tools can help isolate and repair bad sectors without a full format. Be sure to backup your data and weigh your options carefully before proceeding with bad sector removal.