How to Use Microsoft System File Checker or Sfc /Scannow
Microsoft System File Checker is a useful, built-in utility that can scan for and restore corrupted files in Windows. It is often used and recommended by techs and advanced users, however, it's relatively simple to use. Here's all you need to know to use System File Checker or Sfc /Scannow in text and video format.
Windows 10, Windows 8.1, or Windows 8 users will need to first run the Deployment Image Servicing and Management (DISM) tool before running the System File Checker. DISM will use Windows Update to provide any files that are needed to fix corruption. If you skip this step, System File Checker might not work. Windows 7 and Vista users can skip this step.
Type in DISM.exe /Online /Cleanup-image /Restorehealth and press enter. This may take a few minutes.
2: Running System File Checker
All you need to do is type in sfc /scannow and press the Enter key.
System File Checker will now scan for and replace files from the Windows cache, typically located at C:\Windows\System32\dllcache.
Once completed, you should see one of four possible results:
Windows Resource Protection did not find any integrity violations - You should be good to go as no issues were found.
Windows Resource Protection could not perform the requested operation - Run SFC from safe mode and also verify PendingDeletes, and PendingRenames folders exist under C:\WinSxS\Temp
Windows Resource Protection found corrupt files and successfully repaired them - Problems were found and fixed. Microsoft has a page here to show you how to view details.
Windows Resource Protection found corrupt files but was unable to fix some of them - Odds are the file couldn't be replaced, and you'll need to do so manually. Scroll back up to see how to view the log file to locate the file in question.
This command will place sfcdetails.txt on your Desktop. Look for the date you ran the System File Checker, and you can see what it did. The log file is a bit of a scrambled mess, yet not too hard to decipher once you find the date you ran SFC. Typically, you're looking for what wasn't repaired so you can further troubleshoot your problem.