How to Fix Corrupted System Files on Windows (SFC & DISM)

If your Windows apps are crashing or you are seeing random system errors, your core OS files have likely become corrupted. This is a common hurdle that happens during updates or unexpected shutdowns, but it is usually repairable without needing a full reinstall.

What you will need

You will need administrative access to your computer to run these system-level repair tools.

Steps

1. 01
   Press the Windows key, type CMD, right-click 'Command Prompt', and select 'Run as administrator'. Click 'Yes' on the permission prompt to open the terminal with full access.
2. 02
   Type sfc /scannow and press Enter. This command initiates a scan of all protected system files and replaces corrupted files with a cached copy.
3. 03
   Wait for the scan to reach 100 percent. If it reports that it found and fixed integrity violations, restart your computer and your issue should be resolved.
4. 04
   If the scan reports errors it could not fix, type DISM /Online /Cleanup-Image /RestoreHealth and press Enter to download fresh system files from Windows Update servers.
5. 05
   Once the DISM tool completes, run sfc /scannow one more time. This ensures that the new files are correctly applied to your system and repairs any remaining discrepancies.

Still not working?

If you are still receiving errors after running these commands, check the CBS log located at C:/Windows/Logs/CBS/CBS.log for specific details on what is failing. If the logs show consistent read-write errors, your physical hard drive or SSD may be starting to fail and should be tested with diagnostic software immediately.

Frequently asked questions

Will running these commands delete my personal files?

No, these commands only scan and repair Windows system files and will not affect your personal documents, photos, or installed applications.

How often should I run these scans?

You only need to run these if you notice system instability or specific error messages; they are not required for routine maintenance.

What should I do if DISM gets stuck at 20 percent?

DISM can sometimes appear to hang during the process. Give it at least 15 to 20 minutes to complete before assuming it has frozen or closing the window.