System File Checker (SFC) is a built-in Windows 10 tool that scans protected system files and replaces damaged or missing ones with a correct copy. It’s one of the first things to try when Windows crashes, apps won’t open, features stop working, or you see strange errors after an update or power loss. This guide shows how to run it properly, what the results mean, how to pair it with DISM, and what to do if SFC can’t fix everything.
Note: Windows 10 reached end of support on October 14, 2025. Consumer Extended Security Updates (ESU) now run until October 12, 2027. These steps still work on Windows 10, but upgrading to Windows 11 is the long-term way to keep getting security fixes.
Quick Answer
Search for cmd, right-click Command Prompt, and choose Run as administrator. Type sfc /scannow and press Enter. Wait for Verification 100% complete, read the result, and restart your PC.
Step 1: Open an Administrator Command Prompt
- Click Start and type cmd.
- Right-click Command Prompt and choose Run as administrator. Click Yes at the prompt.
- The title bar should say Administrator: Command Prompt. SFC won’t run in a normal window.
PowerShell or Windows Terminal (Admin) work too; the commands are the same.
Step 2: Run DISM First (Recommended)
SFC repairs files using a local copy called the component store. If that store is damaged, SFC can’t fix everything. Running DISM first repairs the store from Windows Update:
- Type
DISM /Online /Cleanup-Image /RestoreHealthand press Enter. - Wait until it reaches 100% and says The restore operation completed successfully. It can pause at 20% or 62% for several minutes; that’s normal.
You need an internet connection for this step. For more detail, see our guide on running DISM (the commands are identical on Windows 10).
Step 3: Run the SFC Scan
- Type
sfc /scannowand press Enter. - Leave the window open. The scan usually takes 5 to 20 minutes.
- When it finishes, read the message and restart your PC.
What SFC Results Mean
| Message | What it means | What to do |
|---|---|---|
| Windows Resource Protection did not find any integrity violations. | No corrupted system files. | Look for other causes (drivers, apps, disk). |
| Windows Resource Protection found corrupt files and successfully repaired them. | Problems fixed. | Restart. Run SFC once more to confirm. |
| Windows Resource Protection found corrupt files but was unable to fix some of them. | Some files couldn’t be repaired. | Run DISM, restart, and run SFC again; see advanced steps below. |
| Windows Resource Protection could not perform the requested operation. | SFC couldn’t run. | Run SFC in Safe Mode or from Windows Recovery. |
| There is a system repair pending which requires reboot to complete. | A pending update blocks the scan. | Restart and run SFC again. |
Advanced: When SFC Can’t Fix Everything
See which files failed
Run this to copy SFC entries from the log to your desktop:
findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log > "%userprofile%\Desktop\sfcdetails.txt"
Open sfcdetails.txt and look for lines with “Cannot repair member file.”
Run SFC in Safe Mode
Programs running in the background can interfere. Restart into Safe Mode (Settings > Update & Security > Recovery > Advanced startup > Troubleshoot > Advanced options > Startup Settings > Restart, then press 4) and run SFC again.
Run SFC offline from Windows Recovery
- Go to Advanced startup and choose Troubleshoot > Advanced options > Command Prompt.
- Find your Windows drive letter (it may not be C: in recovery): type
bcdeditand check the osdevice line, or usedir D:\to look for the Windows folder. - Run
sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows, replacing C with the correct letter.
Check the disk
Bad sectors can corrupt files again. Run chkdsk C: /scan to check the drive, or chkdsk C: /f to fix errors on the next restart.
Last resorts
If corruption persists, try System Restore, an in-place upgrade (run setup from Windows 10 installation media and keep files and apps), or Reset this PC.
Other SFC Options
sfc /verifyonly— scans without repairing.sfc /scanfile=C:\Windows\System32\filename.dll— checks and repairs one file.sfc /verifyfile=path — checks one file without repairing.
Related: Fix the Invalid Value for Registry error in Windows 10.
Related: Install drivers in Safe Mode on Windows 10.
Related: How to fix corrupted system files in Windows 10.
Related: Register a DLL in Windows 10.
Frequently Asked Questions
Is it safe to run SFC?
Yes. It only replaces protected Windows files with correct versions and doesn’t touch your personal files.
Can I use my PC during the scan?
You can, but it’s best to avoid heavy work and don’t close the window until it finishes.
How often should I run SFC?
Only when you notice problems. There’s no benefit to running it on a schedule.
Summary
- Open Command Prompt as administrator.
- Run
DISM /Online /Cleanup-Image /RestoreHealth. - Run
sfc /scannowand restart. - If files can’t be repaired, check the CBS log, try Safe Mode or offline SFC, and check the disk.
Kermit Matthews is a freelance writer based in Philadelphia, Pennsylvania with more than a decade of experience writing technology guides. He has a Bachelor’s and Master’s degree in Computer Science and has spent much of his professional career in IT management.
He specializes in writing content about iPhones, Android devices, Microsoft Office, and many other popular applications and devices.