SFC Scannow Windows 11: How to Run It and Read the Results

Running an sfc scannow Windows 11 check is one of the safest repairs you can try when Windows features misbehave, apps crash for no clear reason, or the system feels unstable. System File Checker (SFC) scans protected Windows system files and replaces any that are missing or corrupted with a known-good copy. It does not touch your documents or apps. The catch is that SFC is only as good as its repair source, which is why Microsoft now pairs it with DISM.

When SFC is worth running

SFC is a good next step when:

• Built-in parts of Windows fail, such as Settings pages that will not open, a broken Start menu or a search box that does nothing.
• You see errors about missing DLL files from Windows components.
• Updates fail repeatedly, or the PC has had an unexpected power loss during an update.
• You get blue screens with the SYSTEM_SERVICE_EXCEPTION stop code, for which Microsoft specifically suggests SFC.

It will not fix third-party app bugs, driver faults or hardware problems. If those are suspected, see the Windows 11 troubleshooting hub for the right tool.

SFC and DISM: what each one checks

It helps to know how the two tools divide the work:

• SFC looks at the protected Windows files your PC actually runs, such as system DLLs and drivers, and swaps any damaged copy for a clean one.
• DISM looks at the component store under C:\Windows\WinSxS, which is where those clean copies come from.

If the store is healthy, SFC alone can fix most file damage. If the store is damaged too, SFC reports files it cannot fix, and only DISM can sort out the source. Running both, in the order below, covers both cases in one sitting.

Step 1: Open an elevated Command Prompt

SFC needs administrator rights.

1. Select Start and type cmd.
2. Right-click Command Prompt and select Run as administrator.
3. Select Yes in the User Account Control prompt.

You can also right-click Start and select Terminal (Admin). Either works; the window title should begin with “Administrator”.

Before you start, Microsoft recommends installing the latest updates and restarting, so you scan a fully updated system.

Step 2: Run DISM before SFC

SFC repairs files by copying them from the Windows component store. If that store is itself damaged, SFC has nothing good to copy. Microsoft’s current guidance is to run DISM first:

DISM.exe /Online /Cleanup-image /Restorehealth

Note the space before each slash. It can take several minutes and may appear to pause at certain percentages. Wait for “The operation completed successfully”. DISM uses Windows Update to fetch replacement files by default, so stay online. For more detail, including what to do when DISM cannot reach Windows Update, see our DISM RestoreHealth guide.

Step 3: Run sfc /scannow

In the same window, type:

sfc /scannow

There is a space between sfc and the slash. The scan runs in stages and reports a percentage. Do not close the window until it says verification is 100% complete. On a modern SSD this usually takes minutes.

Step 4: Understand the result

SFC ends with one of four messages:

Message	What it means	What to do
Windows Resource Protection did not find any integrity violations.	System files are fine.	Look elsewhere: drivers, apps or hardware.
Windows Resource Protection found corrupt files and successfully repaired them.	Problems were found and fixed.	Restart, then run SFC again to confirm.
Windows Resource Protection found corrupt files but was unable to fix some of them.	Some files could not be repaired from the store.	Run DISM again, then SFC, and check CBS.log.
Windows Resource Protection could not perform the requested operation.	The scan could not run.	Run SFC in safe mode, and check that PendingDeletes and PendingRenames exist under C:\Windows\WinSxS\Temp.

For the safe mode route, see our Windows 11 safe mode guide.

Step 5: Read CBS.log to see what SFC did

SFC writes its details to C:\Windows\Logs\CBS\CBS.log. That file is large and mixes in other servicing activity, so Microsoft suggests extracting only the SFC lines, which are tagged [SR]:

findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"%userprofile%\Desktop\sfcdetails.txt"

Run it in the administrator window, then open sfcdetails.txt from your desktop.

What to look for:

• Each line starts with a date and time. The file includes every SFC run on the PC, so focus on lines from the run you just did.
• “Verifying” lines are routine progress entries.
• “Repaired file” or similar wording means a file was replaced successfully.
• “Cannot repair member file” names a file SFC could not fix, followed by the component it belongs to. Those are the files that matter.

If you see “Cannot repair” entries, run DISM /RestoreHealth again (with a /Source if Windows Update is not working), then rerun SFC. Microsoft also documents manually replacing a file with a known-good copy from a PC running the same Windows version, using takeown and icacls, but that is an advanced step and an easy way to break things if the versions do not match exactly.

If SFC keeps finding problems

If SFC still reports unfixable files after DISM has run successfully, the faster route is usually to repair Windows as a whole:

• Fix problems using Windows Update: Settings > System > Recovery > Reinstall now. This reinstalls your current version while keeping apps, files and settings.
• Reset this PC: a full reinstall, covered in our Reset this PC guide.

Repeated corruption after repairs can also point to a failing drive or faulty memory, so check those if the problem keeps coming back. Our blue screen guide covers running Windows Memory Diagnostic.

SFC checks Windows files, not the drive itself; to check the file system for errors, run CHKDSK in Windows 11.