Scans and verifies the versions of all protected system files after you restart your computer.
Syntax

sfc [/scannow] [/scanonce] [/scanboot] [/revert] [/purgecache] [/cachesize=x]

Parameters

/scannow : Scans all protected system files immediately.

/scanonce : Scans all protected system files once.

/scanboot : Scans all protected system files every time the computer is restarted.

/revert : Returns the scan to its default operation.

/purgecache : Purges the Windows File Protection file cache and scans all protected system files immediately.

/cachesize=x : Sets the size, in MB, of the Windows File Protection file cache.

/? : Displays help at the command prompt.
Top of pageTop of page
Remarks

You must be logged on as a member of the Administrators group to run sfc.

If sfc discovers that a protected file has been overwritten, it retrieves the correct version of the file from the %systemroot%system32dllcache folder, and then replaces the incorrect file.

If the %systemroot%system32dllcache folder becomes corrupt or unusable, use sfc /scannow, sfc /scanonce, or sfc /scanboot to repair the contents of the Dllcache directory.

System File Checker (sfc)