Article ID: 222471 - Last Review: February 23, 2007 - Revision: 4.4

Description of the Windows 2000 System File Checker (Sfc.exe)

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This article was previously published under Q222471

For a Microsoft Windows XP and Windows Server 2003 version of this article, see 310747 (http://support.microsoft.com/kb/310747/EN-US/ )

Notice

This article applies to Windows 2000. Support for Windows 2000 ends on July 13, 2010. The Windows 2000 End-of-Support Solution Center (http://support.microsoft.com/?scid=http%3a%2f%2fsupport.microsoft.com%2fwin2000) is a starting point for planning your migration strategy from Windows 2000. For more information see the Microsoft Support Lifecycle Policy (http://support.microsoft.com/lifecycle/) .

SUMMARY

This article describes the System File Checker tool (Sfc.exe) that is used with the Windows File Protection (WFP) feature.

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MORE INFORMATION

The System File Checker tool gives an administrator the ability to scan all of the protected files to verify their versions. The System File Checker tool also checks and repopulates the %SystemRoot%\System32\Dllcache folder. If the Dllcache folder becomes damaged or unusable, you can use either the sfc /scanonce or sfc /scanboot command to repair the contents of the folder.

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System File Checker Tool Syntax

The /scannow command scans all protected system files and replaces incorrect versions with correct Microsoft versions. This command also repopulates the DLLCache folder with the most recent versions of protected files. This requires access to the Windows installation source files and also the installed Service Pack files. You are usually prompted for the location of these files during the scan operation.
The /scanonce command scans all protected system files once. This command requires access to the Windows installation source files.
The /scanboot command scans all protected system files every time that you start your computer. This command requires access to the Windows installation source files.
The /cancel command cancels all pending scans of protected system files.
The /enable command enables WFP for normal operation.
The /purgecache command purges the file cache and scans all of the protected system files immediately. This command requires access to the Windows installation source files. This command is required after you run the /cachesize=x command.
The /cachesize=x command sets the file cache size in megabytes (MB). This command requires a reboot followed by a /purgecache command to adjust the size of the on-disk cache.
The /quiet command replaces all incorrect file versions without prompting the user.