Corrupted system files can cause crashes, blue screens, apps that won’t open, Start menu or search problems, and failed updates. Windows 10 includes two built-in tools that find and replace damaged files: DISM, which repairs the Windows image that serves as the source for good copies, and SFC (System File Checker), which checks your system files against that image and swaps in clean versions. Run them in that order, and most corruption is fixed without losing any files or apps.
Note: Windows 10 reached end of support in October 2025. These steps still work, and the same commands work in Windows 11.
Quick answer
Open Command Prompt as administrator and run these two commands, one at a time:
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow
Restart your PC when both finish.
Step 1: Open Command Prompt as administrator
Click Start, type cmd, right-click Command Prompt, and choose Run as administrator. Click Yes on the User Account Control prompt. Windows PowerShell (Admin) works too.
Step 2: Repair the Windows image with DISM
Type this command and press Enter:
DISM /Online /Cleanup-Image /RestoreHealth
DISM checks the component store, the folder of original files Windows uses for repairs, and downloads clean copies from Windows Update if needed. It usually takes 5 to 20 minutes. The progress bar can sit at 20% or 62% for a long time. That’s normal, so let it finish.
When it’s done, you should see “The restore operation completed successfully.” Our guide on running DISM explains the other DISM options, such as /CheckHealth and /ScanHealth.
Step 3: Run System File Checker
In the same window, type:
sfc /scannow
SFC scans every protected system file and replaces damaged ones. It takes about 10 to 30 minutes. Don’t close the window until it reaches 100%. For a closer look at this tool, see how to run an SFC scan in Windows 10.
Step 4: Read the result
- “Windows Resource Protection did not find any integrity violations.” Your system files are fine. The problem is somewhere else.
- “Windows Resource Protection found corrupt files and successfully repaired them.” Restart your PC. The issue should be fixed.
- “Windows Resource Protection found corrupt files but was unable to fix some of them.” Restart and run
sfc /scannowagain. If it still fails, try the steps below. - “Windows Resource Protection could not perform the requested operation.” Run SFC from Safe Mode or the recovery environment, covered below.
Step 5: Restart and test
Restart the computer and check whether the original problem is gone. Some repairs only take effect after a restart.
If SFC can’t fix everything
Run SFC in Safe Mode
Hold Shift while clicking Restart, then go to Troubleshoot > Advanced options > Startup Settings > Restart, and press 4 for Safe Mode. Open Command Prompt as admin and run sfc /scannow again. Fewer programs are running, so fewer files are locked.
Check the disk for errors
Bad sectors on the drive can corrupt files again after they’re repaired. Run chkdsk C: /f in an admin Command Prompt, type Y to schedule it, and restart. The check runs before Windows loads.
Run SFC from the recovery environment
If Windows won’t start, boot into the recovery environment (it appears after a few failed starts, or from a Windows 10 USB drive). Choose Troubleshoot > Advanced options > Command Prompt, and run:
sfc /scannow /offbootdir=C:\ /offwindir=C:\Windows
The drive letter may be different in the recovery environment. Type dir C: to confirm that C: contains the Windows folder.
Repair install (keeps files and apps)
Download the Media Creation Tool from Microsoft, run it inside Windows, and choose Upgrade this PC now. Select Keep personal files and apps. This reinstalls Windows over itself and replaces every system file.
Reset this PC
As a last resort, go to Settings > Update & Security > Recovery > Reset this PC. Choose Keep my files to keep personal files but remove apps. Back up first.
What causes corrupted system files?
- Sudden power loss or forced shutdowns during updates
- A failing hard drive or SSD
- Malware
- Faulty or interrupted Windows updates
- Third-party “tweak” or cleaner tools that modify system files
Tips
- Run DISM before SFC. If the repair source is damaged, SFC can’t fix files correctly.
- Close other programs and keep the PC plugged in while the scans run.
- SFC writes details to C:\Windows\Logs\CBS\CBS.log if you want to see which files were repaired.
- Run a malware scan with Windows Security if corruption keeps coming back.
Related: How to use DISM to repair Windows 10.
Frequently asked questions
Will SFC or DISM delete my files?
No. They only replace Windows system files. Your documents, photos, and apps aren’t touched.
Do I need an internet connection?
DISM uses Windows Update to download clean files, so it works best online. SFC works offline.
How often should I run these tools?
Only when you have a problem. There’s no benefit to running them on a schedule.
Summary
- Open Command Prompt as administrator.
- Run DISM /Online /Cleanup-Image /RestoreHealth.
- Run sfc /scannow.
- Restart, and use Safe Mode, CHKDSK, or a repair install if problems remain.
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.