How to Run System File Checker sfc /scannow in Windows

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.

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

1. From the desktop, press the Windows + X shortcut key combination.
2. In the menu, select Command Prompt (Admin).
   NOTE: System File Checker can be run from Windows PowerShell (Admin).
3. On the User Account Control (UAC) prompt, click Yes.
4. In the command prompt window, type SFC /scannow and press Enter.
5. The system file checker utility checks the integrity of Windows system files and repairs them if required.
6. 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

1. Create a Windows installation disk using the Dell OS Recovery tool.
2. Connect the USB installation disk to the computer.
3. Turn on the computer and tap the F12 key until you enter the One Time Boot Menu.
4. Select the USB drive from the list and press Enter.
5. The computer boots using the USB installation disk.
6. Select your Language, and then click Next.
7. Select the Repair your Computer option.
8. Click Troubleshoot, and then Advanced Options.
9. Select Command Prompt from the list.
10. Type sfc /scannow /offbootdir=c:\ /offwindir=c:\windows and press Enter.
11. The system file checker utility checks the integrity of Windows system files and repairs them if required.
12. After the process is complete, reboot 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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