Error: "Windows detected file system corruption on OS (C:). You must check disk for errors before it can be restored" while running System Restore.

I am not tech savvy so please bare with me.

I tried system restore and got this message:

Windows detected file system corruption on OS (C:). You must check disk for errors before it can be restored.

OK did nothing, so my dad checked for errors for me and none were found.

We tried to restore again and got the same message.

Also, Disk defragment only shows Recovery Drive and doesn't respond to the Analyze or Defragment buttons. I'm pretty sure this is related to the above problem because they occured at the same time.

Please try to help in a way a complete idiot can understand. I really appreciate any help. Thank You.


Hi jolieisanangel,


The most prominent reason for the error message is file system corruption on the hard disk. It can also occur due to corruption of Windows system files.


Disk defragment not responding to Analyze or Defragment buttons can be attributed to corrupt files, folders, or bad sectors on the hard disk. If a disk that you're expecting to see under Current status is not showing up there, it might be because it contains an error. Try to repair the disk first, and then return to Disk Defragmenter to try again.


 You can try executing SFC /SCANNOW command and then run CHKDSK /F command to repair file system issues.


Step 1: Run System File Checker (SFC) scan


Detailed explanation on how to run the scan is provided in the article below.



How to use the System File Checker tool to troubleshoot missing or corrupted system files on Windows Vista or on Windows 7


In case SFC scan doesn’t repair the files, follow the steps given in the link above to repair those corrupted files.


In addition, follow Step 2.


Step 2: Run CHKDSK /F


Chkdsk scans your hard drive for errors, bad blocks and sectors, and can help determine the general health of your PC. The Chkdsk /F function takes Chkdsk a step further, helping you to automatically fix problems on your system.

Follow these steps to do so.


1.    Click Start, and then Run.

2.    In Open, type cmd, and then press ENTER.

3.    To run chkdsk on C drive, type  chkdsk c: /f, and then press Enter.


Note If one or more of the files on the hard disk are open, you will receive the following message:


Chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts? (Y/N)


Type Y, and then press Enter to schedule the disk check, and then restart your computer to start the disk check.


More Chkdsk commands can be found here. Information holds equally good for Windows 7.

Important:While performing chkdsk on the hard drive, if any bad sectors are found on the drive data available on that might be lost when chkdsk tries to repair that sector.


Step 3: Run disk defragment from command prompt


Once you run both the steps, test if disk defragment works. Perform this test from the command prompt.


Here’s how:


1.    Go to  start and type cmd.

2.    Right-click oncmd and select “Run as administrator”.

3.    To Perform an Analysis of C: drive:


a)   Type the command below.

defrag.exe c: -a

b)   Press Enter.


2.    To Defragment a drive, type the command below and press  Enter.


a)   Type the command below.

defrag.exe c: for the C: drive

Note: You can choose the drive letter according to your choice.

 defrag.exe -cfor all drives or volumes.


b)   Press Enter.


See if disk defragmentation goes successful.


Once you perform all the steps given above, try performing system restore.


Here are answers to some common questions about System Restore.


System Restore: frequently asked questions


Shinmila H - Microsoft Support

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Question Info

Last updated July 14, 2020 Views 29,593 Applies to: