How to Check If Your Windows 11 Installation Is Genuine and Intact

What an installer integrity check does and why you might need one

An installer integrity check verifies that your Windows 11 installation files have not been corrupted, modified, or damaged since they were installed. Windows includes a built-in tool called the System File Checker (SFC) that scans your system files and repairs them if they are broken. A second tool, the Deployment Image Servicing and Management utility (DISM), checks the health of the Windows image itself — the underlying structure that holds all your system files together.

You would run these checks if Windows is crashing unexpectedly, programs are failing to open, you are seeing repeated error messages, or your computer is running much slower than normal. These tools can often fix the problem without requiring a full Windows reinstall. They are also useful after a major Windows update if something went wrong during installation.

Key Takeaways

The System File Checker (SFC) scans and repairs corrupted Windows system files, and you run it by typing a single command in Command Prompt as administrator.
DISM checks the Windows image health and can repair it, and should be run before SFC if you suspect deep corruption.
Both tools require you to open Command Prompt as administrator — right-click the Command Prompt icon and select "Run as administrator".
A full scan takes 15 to 30 minutes and will restart your computer if repairs are made, so close your work first.
If both tools find no problems, your Windows installation is intact; if they find and repair problems, restart and test whether your issue is resolved.

Opening Command Prompt as administrator

Both the SFC and DISM tools require administrator permissions to run. The fastest way is to use the search box on your taskbar. Click the Windows icon at the bottom left of your screen, type Command Prompt, and you will see the Command Prompt app appear in the search results. Do not click it directly — instead, right-click on it and select Run as administrator. Windows will ask for permission; click Yes.

You will now see a black window with a blinking cursor. The window title should say "Administrator: Command Prompt" at the top. If it does not say "Administrator", you are not running it with the correct permissions and the tools will not work. Close this window and try again.

Running the System File Checker scan

In the Command Prompt window, type the following exactly as written and then press Enter:

sfc /scannow

The scan will begin when ready. You will see a progress bar that says "Scanning system files" and a percentage that increases as the scan runs. This process takes 15 to 30 minutes depending on how many files Windows needs to check. Do not close the Command Prompt window or restart your computer while the scan is running.

When the scan finishes, you will see one of three messages. If it says "Windows Resource Protection did not find any integrity violations", your system files are intact and you can close the window. If it says "Windows Resource Protection found corrupt files and successfully repaired them", the tool has fixed the problems — close the window and restart your computer, then test whether your issue is resolved. If it says "Windows Resource Protection found corrupt files but was unable to fix some of them", you will need to run the DISM tool before trying SFC again.

Running the DISM image health check

If the SFC scan found problems it could not repair, or if you want to check the Windows image itself before running SFC, use DISM. In the Command Prompt window (still running as administrator), type the following and press Enter:

DISM /Online /Cleanup-Image /ScanHealth

This scan checks the Windows image for corruption. It is faster than SFC and takes 5 to 10 minutes. When it finishes, it will tell you whether the image is healthy or has corruption. If it reports corruption, run the repair command next.

To repair the image, type the following and press Enter:

DISM /Online /Cleanup-Image /RestoreHealth

This command downloads replacement files from Microsoft's servers and rebuilds any damaged parts of the Windows image. It requires an internet connection and takes 15 to 45 minutes. When it finishes, you can close Command Prompt and restart your computer. After the restart, run the SFC scan again to check whether any system files need repair.

What to do if the scans find no problems

If both SFC and DISM report that your Windows installation is healthy and intact, the problem you are experiencing is not caused by corrupted system files. In this case, the issue is likely caused by a third-party program, a driver, or a hardware problem. Try uninstalling any recently installed software, update your device drivers through Device Manager, or run a virus scan using Windows Defender.

If you are still experiencing crashes or errors after confirming your Windows installation is intact, you may need to troubleshoot the specific error message you are seeing. Write down the exact error text and search for it online, or contact the manufacturer of the hardware or software that is failing.

Restarting after repairs are made

If either SFC or DISM made repairs, you must restart your computer for the changes to take effect. Close all open programs and save any work first. You can restart by typing the following in Command Prompt and pressing Enter:

shutdown /r /t 0

This restarts your computer when ready. Alternatively, click the Windows icon, select the power icon, and click Restart. After the restart, your computer may take longer than usual to start up as Windows applies the repairs. Once you are back at the desktop, test whether the problem that prompted you to run the scan has been resolved.

Frequently Asked Questions

Can I run these scans while using my computer normally?

You can run them while other programs are open, but the scan will be slower and may be interrupted if Windows needs to restart. Close all programs and browser windows before starting, especially if you are running SFC or DISM for the first time.

What if Command Prompt says "Access Denied" when I type the command?

This means you did not open Command Prompt as administrator. Close the window, right-click on Command Prompt in the search results, and select "Run as administrator" again. Make sure the window title says "Administrator: Command Prompt" before typing the command.

Do I need to run both SFC and DISM, or just one?

Start with SFC if you are not sure. If SFC finds problems it cannot repair, then run DISM to repair the Windows image, and run SFC again afterward. If you suspect deep corruption or a failed Windows update, run DISM first.

How often should I run these scans?

Run them only when you are experiencing problems — crashes, errors, or unusual behavior. Running them regularly as maintenance is not necessary and will not prevent problems from occurring.

Will these scans delete my files or programs?

No. Both SFC and DISM repair system files only. They do not touch your documents, photos, programs, or personal files. Your data is safe.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.