Use the System File Checker tool to repair missing or corrupted system files

If some Windows functions aren't working or Windows crashes, use the System File Checker to scan Windows and restore your files.  
 
Though the steps below might look complicated at first glance, just follow them in order, step-by-step, and we’ll try to get you back on track.

 

Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search. Type Command Prompt in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
Command prompt - Run as administrator (Windows 8 or 8.1) 

 

To do this, click Start, type Command Prompt or cmd in the Search box, right-click Command Prompt, and then click Run as administrator. If you are prompted for an administrator password or for a confirmation, type the password, or click Allow.
Command prompt - Run as administrator 

More Information

How to view details of the System File Checker process

To view the details that included in the CBS.Log file, you can copy the information to the Sfcdetails.txt file by using the Findstr command, and then view the details in the Sfcdetails.txt. To do this, follow these steps:

  1. Open an elevated command prompt as described in the previous step 1.

  2. At the command prompt, type the following command, and then press ENTER:

    findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"%userprofile%\Desktop\sfcdetails.txt" 

    Note The Sfcdetails.txt file contains details from every time that the System File Checker tool has been run on the computer. The file includes information about files that were not repaired by the System File Checker tool. Verify the date and time entries to determine the problem files that were found the last time that you ran the System File Checker tool.

  3. Open the Sfcdetails.txt file from your desktop.

  4. The Sfcdetails.txt file uses the following format:

    Date/Time SFC detail The following sample log file contains an entry for a file that could not be repaired: 2007-01-12 12:10:42, Info CSI 00000008 [SR] Cannot repair member file [l:34{17}]"Accessibility.dll" of Accessibility, Version = 6.0.6000.16386, pA = PROCESSOR_ARCHITECTURE_MSIL (8), Culture neutral, VersionScope neutral, PublicKeyToken = {l:8 b:b03f5f7f11d50a3a}, Type neutral, TypeName neutral, PublicKey neutral in the store, file is missing


How to manually replace a corrupted system file with a known good copy of the file

After you determine which system file was corrupted and could not be repaired through the detail information in the Sfcdetails.txt file, find where the corrupted file located, and then manually replace the corrupted file with a known good copy of the file. To do this, follow these steps:

Note You may be able to get a known good copy of the system file from another computer that is running the same version of Windows with your computer. You may perform a System File Checker process on that computer to make sure the system file that you intend to copy is a good copy.

  1. Take administrative ownership of the corrupted system file. To do this, at an elevated command prompt, copy and then paste (or type) the following command, and then press ENTER:

    takeown /f Path_And_File_Name Note The Path_And_File_Name placeholder represents the path and the file name of the corrupted file. For example, type takeown /f C:\windows\system32\jscript.dll. 
    Command Prompt with administrator rights - command succeeded

  2. Grant administrators full access to the corrupted system file. To do this, copy and paste (or type) the following command, and then press ENTER:

    icacls Path_And_File_Name /GRANT ADMINISTRATORS:F Note The Path_And_File_Name placeholder represents the path and the file name of the corrupted file. For example, type icacls C:\windows\system32\jscript.dll /grant administrators:F.
    Command Prompt with administrator rights

  3. Replace the corrupted system file with a known good copy of the file. To do this, copy and paste (or type) the following command, and then press ENTER:

    Copy Source_File Destination Note The Source_File placeholder represents the path and file name of the known good copy of the file on your computer, and the Destination placeholder represents the path and file name of the corrupted file. For example, type copy E:\temp\jscript.dll C:\windows\system32\jscript.dll.

If the steps above don't work, you may need to reinstall Windows. For more info, see Windows 10 recovery options.

Need more help?

Expand your skills
Explore Training
Get new features first
Join Microsoft Insiders

Was this information helpful?

Thank you for your feedback!

×