Windows Repair

SFC Scannow Explained: What It Does and When to Use It

Understand what sfc /scannow does, when to run it, whether it is safe, and why Administrator permission is required.

sfc /scannow runs the Windows System File Checker. It scans protected Windows system files and attempts to repair missing or corrupted files.

Command

sfc /scannow

Does it delete personal files?

No. SFC is designed to repair Windows system files. It does not delete your documents, photos, desktop files, or downloads.

Does it need Administrator permission?

Yes. Open Command Prompt or PowerShell as Administrator before running it.

When should you use it?

  • Windows apps or system features behave strangely.
  • Windows updates failed or left the system unstable.
  • You see errors related to missing or corrupted system files.
  • You already tried a restart and basic troubleshooting.

SFC vs DISM

If SFC cannot repair files, run DISM RestoreHealth and then run SFC again.