Unstable sectors or bad blocks are segments of your hard drive that cannot be read by the controller properly. Such problems occur over time due to physical wear out of the HDD or program errors. If your disk has a lot of unstable sectors, it might result in freezes and system failures. However, it is possible to fix your hard disk with special software.

Two easy methods to repair unstable sectors

First of all, you must accept that having a small number of bad blocks is normal. Especially, if you are using your disk for a while. However, when this number exceeds an acceptable limit, you will better try to restore or block unstable sectors.

Method #1: using the Victoria utility

Sectors are marked as «unstable» when the discrepancy between written information and the checksum is found. It happens due to writing failures from time to time. Such sectors can be fixed by erasing the data that was incorrectly written before. We would recommend using the tool called Victoria for this purpose:

  • Install the program and launch it.
  • Start SMART scan to find unstable sectors on your disk.
  • Select one of the available options: Remap, Restore, Erase, Ignore.
Repair Unstable Sectors using the Victoria utility
  • Wait for the procedure to end.

This is a free software that can be used for analyzing physical and logical drives. It also does a good job with minor HDD repairs such as bad/unstable sectors.

Method #2: using standard Windows tools

You can also check and repair bad sectors with a Check Disk tool available in Windows. Just follow these instructions:

  • Run Command Prompt as administrator (press Win+X or right-click the Start menu button and select the needed option).
  • Type chkdsk /r in the window that will appear and hit Enter.
  • If you have initiated a check for the disk with your OS, you will be informed that the volume is busy and it will be checked after the restart (hit Y on your keyboard to confirm).
Repair Unstable Sectors using standard Windows tools

After the reboot, the tool will analyze the disk. If there are any sectors that can be rewritten or fixed, the tool will repair them automatically. If you get an error in the process, it means that you have too many unstable sectors on your drive. In this case, you should probably think about a new HDD or SSD.

Additional recommendations

When the Check Disk tool tells you about an abnormal number of bad blocks and unstable sectors, the easiest way would be to copy important information and stop using that HDD. Especially, if you have been using the disk for a long time, it is highly likely that magnetic tape inside has deteriorated. All fixes and repairs will do no good in this case.

If you lost some data after the HDD error occurred or after exceed the bad sectors limit, it is possible to restore it with specific third-party programs.

We don’t recommend using disks with a high percentage of unstable sectors for saving important documents and files. Installing operating systems on them is also not a good idea. Such devices are too unstable and unpredictable. They should be used only as backup storage devices.

To keep your HDD in good health, you need to check it for errors and bad sectors from time to time and perform defragmentation. If you don’t know how to defrag a hard drive, you should look for the guide on our website.

Summing up today’s guide, we can say that unstable sectors on HDD are nothing to be afraid of as they can be fixed with third-party programs or standard Windows utilities. However, if the percentage of bad blocks is too high, your HDD is nonreformable.