>

Scan and repair Windows system files with SFC

Use the System File Checker to verify every protected Windows system file against known-good copies and automatically replace the damaged ones.

WindowssystemTerminalDiagnosticsLow risk
Open an elevated Command Prompt and run `sfc /scannow` to scan all protected system files and repair any corruption it finds.

01Command

Command
$ sfc /scannow

02What it does

SFC compares every file in the Windows component store's protected list against a manifest and pulls clean replacements from WinSxS or Windows installation media. The scan takes 5-20 minutes and writes progress to the console. Read the summary at the end: it either found no violations, repaired files, or could not fix everything. When it cannot complete a repair, run `DISM /Online /Cleanup-Image /RestoreHealth` first and re-run SFC. Full details are logged in `%windir%\Logs\CBS\CBS.log` (filter with `findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log`).

03Risk

RiskLow risk
RequirementsMust run in an elevated Command Prompt or PowerShell window (Run as administrator).
!Warning: Do not close the console window while the scan is running; interrupting SFC can leave system files in a half-repaired state.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • sfc | Microsoft Learn
    Microsoft · vendor-doc · 2026-09-17
    Evidence: Microsoft documents that 'sfc /scannow' scans the integrity of all protected system files and replaces incorrect versions with correct Microsoft versions.
  • System File Checker (sfc) - Windows CMD
    SS64 · technical · 2026-09-17
    Evidence: SS64 describes the /scannow switch as scanning all protected system files immediately and repairing problems found.

Last verified: 2026-09-17 · Category: System & Settings

06Related solutions

Repair the Windows component store with DISM RestoreHealth
WindowssystemTerminalDiagnostics

Use the Deployment Image Servicing and Management tool to detect and repair corruption in the Windows component store, the layer SFC depends on.

Medium risk ✓ 2026-09-17
Install any app from the command line with winget
WindowssystemTerminaldeveloper

Use Windows Package Manager to install, search, and upgrade thousands of applications from the community repository in one command.

Low risk ✓ 2026-09-17
Check a drive for file system errors with chkdsk
WindowsFilessystemDiagnostics

Diagnose NTFS file system errors and bad sectors on any volume — including the system drive while Windows is running — before committing to a repair.

Low risk ✓ 2026-09-17