Computer and Software Support


SFC /Scannow 

 Windows Vista and newer

Scans and verifies the versions of all protected system files 

Below is information on the different options of SFC. For directions on using a particular option, click on the hyperlink

  1. /scannow - Scans all protected system files immediately.

  2. /scanonce - Scans all protected system files once.

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

  4. /revert - Returns the scan to its default operation

  5. /purgecache - Purges the Windows File Protection file cache and scan all protected system files immediately.

  6. /cachesize=x -Set the size, in MB, of the windows file protection file cache.

  7. /? - Displays help as the command prompt.

 

NOTES:

  • You must be logged on as 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 %systemroot%system32\dllcache folder, and then replaces the incorrect file.

  • If the %systemroot%\system32\dllcache folder becomes corrupt or unusable, use sfc /scannow, sfc /scanonce, or sfc /scanboot to repair the contents of the Dllcache directory.