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How to Run System File Checker in Windows

Summary: How to use the System File Checker (SFC) command "sfc /scannow" to scan and repair system files in Windows. System File Checker (SFC) helps repair corrupt files that cause boot-related issues. ...

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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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 This hyperlink is taking you to a website outside of Dell Technologies.

How to Run System File Checker (SFC) from within Windows as an Administrator:

Windows 11 and Windows 10

  1. From the desktop, press the Windows + X shortcut key combination.
  2. In the menu, select Command Prompt (Admin).
    NOTE: System File Checker (SFC) 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 (SFC) utility checks the integrity of Windows system files and repairs them if required.
  6. After the process is complete, reboot the computer.

How to Run System File Checker (SFC) Using the Windows Recovery Media

Windows 11 and Windows 10

  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 (SFC) utility checks the integrity of Windows system files and repairs them if required.
  12. 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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Directing the System File Checker (SFC) /scannow Command to Windows

The following steps allow you to boot to a Windows Repair Disk then run the System File Checker (SFC) /scannow command on the appropriately assigned drive.

  1. Boot to your Windows computer repair disk.
  2. When the computer stops at a screen with language and input options, ensure that you have the correct options selected (English, English (United States), and US for USA-based systems) then click Ok.
  3. At the Install Now screen, click Repair Your Computer on the bottom left. If prompted, press Any Key to continue.
  4. Select Keyboard input method (US), click Next.
  5. On the System Recovery Options screen, click the first option, Use recover tools…, click Next.
  6. Then select the Command Prompt hyperlink.
  7. Type the following Command: sfc /scannow /offbootdir=d: /offwindir=d:\windows then press Enter to perform the command.
Note: This assumes that the D: Drive is the correct drive for Windows, it may be different on your computer.

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Affected Products

Alienware, Dell All-in-One, Dell Pro All-in-One, Dell Pro Max Micro, Dell Pro Max Slim, Dell Pro Max Tower, Dell Pro Micro, Dell Pro Slim, Dell Pro Tower, Dell Slim, Dell Tower, Inspiron, OptiPlex, Vostro, XPS, G Series, G Series, Alienware , Dell Plus, Dell Pro, Dell Pro Max, Dell Pro Plus, Dell Pro Premium, Inspiron, Latitude, Dell Pro Rugged, Vostro, XPS, Fixed Workstations, Mobile Workstations, Dell Pro Max Micro XE FCM2250, Dell Pro Max Slim XE FCS1250, Dell Pro Max Tower T2 XE FCT2250, Dell Pro Max 16 XE MC16250, Dell Pro Micro Plus XE QBM1250, Dell Pro Slim Plus XE5 QBS1250, Dell Pro Tower Plus XE5 QBT1250 ...
Article Properties
Article Number: 000126064
Article Type: How To
Last Modified: 30 May 2025
Version:  15
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