Instructions
The Windows System File Checker (SFC) is a tool that is built into all modern versions of Windows. This tool allows you to repair corrupt system files in Windows. System File Checker (SFC) can be run with administrator privileges both from within Windows and using the Windows recovery media.
NOTE: If the System File Checker (SFC) cannot repair corrupt Windows system files, a clean installation of Windows may be the next option.
Learn more about how to Use the System File Checker Tool to Repair Missing or Corrupted System Files 
How to run System File Checker (SFC) from within Windows as an Administrator:
Windows 11, Windows 10, and Windows 8 or 8.1
- From the desktop, press the Windows + X shortcut key combination.
- In the menu, select Command Prompt (Admin).
NOTE: System File Checker can be run from Windows PowerShell (Admin).
- On the User Account Control (UAC) prompt, click Yes.
- In the command prompt window, type
SFC /scannow and press Enter. - The system file checker utility checks the integrity of Windows system files and repairs them if required.
- After the process is complete, reboot the computer.
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How to run System File Checker (SFC) using the Windows Recovery Media
Windows 11, Windows 10, and Windows 8 or 8.1
- Create a Windows installation disk using the Dell OS Recovery tool.
- Connect the USB installation disk to the computer.
- Turn on the computer and tap the F12 key until you enter the One Time Boot Menu.
- Select the USB drive from the list and press Enter.
- The computer boots using the USB installation disk.
- Select your Language, and then click Next.
- Select the Repair your Computer option.
- Click Troubleshoot, and then Advanced Options.
- Select Command Prompt from the list.
- Type
sfc /scannow /offbootdir=c:\ /offwindir=c:\windows and press Enter. - The system file checker utility checks the integrity of Windows system files and repairs them if required.
- After the process is complete, reboot the computer.
NOTE: This process can take up to one hour to complete depending on the configuration of the computer.
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Modifiers
A basic System File Checker (SFC) scan using the /scannow modifier resolves most issues. However, there are other modifiers that can be used.
Modifier function
- /scannow - Scans all system files and replaces corrupted or incorrect files.
- /scanonce - Scans all system files at once.
- /scanboot - Scans all system files at boot each time the system is restarted.
- /cancel - Cancels any pending scans (such as the /scanboot modifier).
- /enable - Enables Windows File Protection (WFP), which prevents programs from modifying Windows system files.
Possible results
There are four possible completion messages that you can receive:
- Windows Resource Protection did not find any integrity violations.
- Windows Resource Protection found corrupt files and successfully repaired them. Details are in the CBS.log:
%inDir%\logs\cbs\cbs.log - Windows Resource Protection found corrupt files but was unable to fix some of them. Details are in the CBS.log:
%Windir%\logs\cbs\cbs.log - Windows Resource Protection could not perform the requested operation.
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Additional Information
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Affected Products
Chromebox, Alienware, Inspiron, Legacy Desktop Models, OptiPlex, Vostro, XPS, G Series, Chromebook, G Series, Alienware, Inspiron, Latitude, Vostro, XPS, Legacy Laptop Models, Fixed Workstations, Mobile Workstations
FAQs
Windows 11, Windows 10, and Windows 8 or 8.1
In the menu, select Command Prompt (Admin). NOTE: System File Checker can be run from Windows PowerShell (Admin). On the User Account Control (UAC) prompt, click Yes. In the command prompt window, type SFC /scannow and press Enter .
How do I run SFC Scannow system file checker? ›
Windows 11, Windows 10, and Windows 8 or 8.1
In the menu, select Command Prompt (Admin). NOTE: System File Checker can be run from Windows PowerShell (Admin). On the User Account Control (UAC) prompt, click Yes. In the command prompt window, type SFC /scannow and press Enter .
How to check for corrupt system files? ›
Steps: Open Command Prompt as Administrator: Press Win + X and select Command Prompt (Admin) or Windows PowerShell (Admin). Run SFC Scan: Type sfc /scannow and press Enter. The scan might take some time to complete. It will automatically repair any corrupted files it finds.
How do I run a system file checker scan in safe mode? ›
Running SFC in Safe Mode and Recovery Mode
- Click the Windows icon on the toolbar, type recovery, then select Recovery options.
- Click Advanced setup, then choose Restart now.
- When the Choose an option window appears, click Troubleshoot, select Advanced options, choose Startup Settings, then click Restart.
The sfc /scannow command will scan all protected system files, and replace corrupted files with a cached copy that is located in a compressed folder at %WinDir%\System32\dllcache.
How do I run a file system check? ›
- From the desktop, press the Windows + X shortcut key combination.
- In the menu, select Command Prompt (Admin). ...
- On the User Account Control (UAC) prompt, click Yes.
- In the command prompt window, type SFC /scannow and press Enter .
If you actually have corrupted or missing Windows files, it should fix them. It doesn't fix other things (bad drivers, bad RAM, bad sectors) so often people are running it as a last ditch effort rather than diagnosing their actual problem.
How do I fix corrupted files in sfc scannow? ›
In the command prompt window, type SFC /scannow and press Enter . The system file checker utility checks the integrity of Windows system files and repairs them if required. After the process is complete, reboot the computer.
How to run a system check on PC? ›
How Do I Run a Diagnostic Test on My Computer?
- On Windows 11, go to Settings > System > Troubleshoot. On Windows 10, go to Settings > Update & Security > Troubleshoot.
- Windows 11 users have an extra step: Select Other troubleshooters.
- Choose a troubleshooter for your problem.
It's a safe command you can run to check integrity of system files.
Full system scan
- Open Windows Security Center (Windows 10) or Windows Security (Windows 11).
- Click on “Virus & threat protection” in the Windows Security window.
- Under the “Virus & threat protection updates” section, click on the “Quick scan” button.
- In the drop-down menu, select “Full scan” instead of “Quick scan.”
Open the Windows Start menu and type “disk cleanup,” then select Run as Administrator. There's a command that checks for important system files that aren't working correctly and fixes them. Open Command Prompt, type “sfc /scannow,” and restart your computer afterward.
How to check SFC scannow results? ›
SFC /SCANNOW and Extracting Results from CBS Log – Windows 8
- Type in sfc /scannow. Type sfc /scannow. ...
- If errors persist. If there are still errors run: ...
- Type sfc /scannow again. Type sfc /scannow again.
- Extract the System File Checker errors from the CBS.log. If there are still errors type: ...
- Search for errors.
Type DISM.exe /Online /Cleanup-image /Restorehealth (note the space before each "/"), and then press Enter. (Note: This step may take a few minutes to start and complete.) After you see a message that says "The operation completed successfully," type sfc /scannow (note the space between "sfc" and "/") and press Enter.
How do I use CHKDSK command to verify and repair system files? ›
Run CHKDSK from the command prompt
- Click on “Start” > type “cmd” > “Run as administrator”.
- Type a CHKDSK command in the command prompt and press “Enter”. Include parameters like “/f”, “/r”, and “/x” to scan and repair any errors. Note: If you opt to only scan your PC for drive errors, type “chkdsk” and press “Enter”.
How to Fix Corrupted Files
- Perform a check disk on the hard drive. Running this tool scans the hard drive and attempts to recover bad sectors. ...
- Use the CHKDSK command. This is the command version of the tool we looked at above. ...
- Use the SFC /scannow command. ...
- Change the file format. ...
- Use file repair software.
You can repair Windows 10 with CMD using the SFC and DISM commands.
- Entering the CMD windows.
- Type in sfc /scannow, and press the Enter key. ...
- If the SFC command doesn't work. ...
- Type in DISM /Online /Cleanup-Image /ScanHealth to scan the corruptions of Windows images.
Whereas CHKDSK finds and fixes errors in the file system of your hard drive, SFC (System File Checker) specifically scans and repairs Windows system files. If it detects a file has been corrupted or modified, SFC automatically replaces that file with the correct version.
Is it safe to run SFC scannow? ›
It's a safe command you can run to check integrity of system files. If there is any system file corruption, it should fix that.
