Should I run SFC or DISM first?

DISM first. Microsoft says to run DISM before System File Checker, because DISM provides the files SFC needs to repair corrupted files.

Does DISM need an internet connection?

By default, DISM uses Windows Update as the source of repair files. With /Source and /LimitAccess, it uses a repair source you name and doesn't contact Windows Update.

How long do the scans take?

Microsoft says the DISM repair may take several minutes. Don't close the Command Prompt window until the SFC verification is 100% complete.

Repair Windows system files with SFC and DISM

To repair Windows system files, open Command Prompt as administrator and run DISM.exe /Online /Cleanup-image /Restorehealth first¹. DISM provides the files needed for the repair and uses Windows Update as its source¹. Then run sfc /scannow, which scans all protected system files and replaces corrupted ones with a cached copy¹. Keep the window open until the scan is 100% complete¹.

Before you start

Missing or corrupted system files can make Windows features fail, cause system errors or make Windows freeze¹. Windows has two built-in repair tools for this. DISM restores damaged Windows components, and System File Checker (SFC) scans for corrupted system files¹.

You need an administrator account, because both tools run in an elevated Command Prompt¹. DISM uses Windows Update as its repair source, so stay online¹. If Windows Update is broken, you can use a running Windows installation or a Windows side-by-side folder from a network share or removable media instead¹.

Each command can take several minutes¹. Don't close the window until SFC reaches 100%¹.

Steps

Open an elevated Command Prompt. Type cmd in the Search box. In the results, right-click Command Prompt and select Run as administrator¹. If Windows asks for confirmation or an administrator password, type the password or click Allow¹.
Check the image first (optional). This scan looks for component store corruption and takes several minutes^2,3:
Command Prompt
```
Dism /Online /Cleanup-Image /ScanHealth
```
Then run this command to see the result. DISM reports whether the image is healthy, repairable or non-repairable²:
Command Prompt
```
Dism /Online /Cleanup-Image /CheckHealth
```
Repair the image with DISM. Type this command and press Enter. It may take several minutes¹:
Command Prompt
```
DISM.exe /Online /Cleanup-image /Restorehealth
```
/RestoreHealth scans the image for component store corruption and then repairs it automatically³.
Use a repair source if Windows Update is broken. Run this command instead of the one in step 3. Replace C:\RepairSource\Windows with the location of your repair source¹:
Command Prompt
```
DISM.exe /Online /Cleanup-Image /RestoreHealth /Source:C:\RepairSource\Windows /LimitAccess
```
/LimitAccess stops DISM from contacting Windows Update³. If you give more than one /Source, DISM copies files from the first location where it finds them².
Run System File Checker. In the same window, type this command and press Enter¹:
Command Prompt
```
sfc /scannow
```
SFC scans all protected system files and replaces corrupted files with a cached copy¹. Don't close the window until the verification is 100% complete¹.

Check it worked

When DISM succeeds, Command Prompt says "The restore operation completed successfully" or "The operation completed successfully"⁴. If you don't see a confirmation message, retype the command and try again⁴.

SFC shows its result when the scan ends¹:

"Windows Resource Protection did not find any integrity violations." You don't have any missing or corrupted system files¹.
"Windows Resource Protection found corrupt files and successfully repaired them." The repair worked¹.

To see what SFC found, copy its entries from the log to a text file on your desktop¹:

Command Prompt

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

The file holds details from every SFC run, so check the date and time of each entry¹.

Common problems

"Windows Resource Protection could not perform the requested operation." Run the SFC scan in safe mode¹. To get there, open Windows RE and select Troubleshoot > Advanced options > Startup Settings > Restart, then pick Enable Safe Mode⁵. Also make sure the PendingDeletes and PendingRenames folders exist under %WinDir%\WinSxS\Temp¹.
"Windows Resource Protection found corrupt files but was unable to fix some of them." Use sfcdetails.txt to find the file SFC couldn't repair¹. Replace it with a known good copy, for example from another computer that runs the same version of Windows¹. Microsoft's steps take ownership of the file, give administrators full access, then copy the good file over it¹:
Command Prompt
```
takeown /f <Path_And_File_Name>
icacls <Path_And_File_Name> /grant administrators:F
Copy <Source_File> <Destination>
```
DISM can't get repair files. By default, DISM gets them from Windows Update¹. Point it at a repair source with /Source and add /LimitAccess, as in step 4^1,3.

Questions

Should I run SFC or DISM first?: DISM first. Microsoft says to run DISM before System File Checker, because DISM provides the files SFC needs to repair corrupted files¹.
Does DISM need an internet connection?: By default, DISM uses Windows Update as the source of repair files¹. With /Source and /LimitAccess, it uses a repair source you name and doesn't contact Windows Update^1,3.
How long do the scans take?: Microsoft says the DISM repair may take several minutes¹. Don't close the Command Prompt window until the SFC verification is 100% complete¹.

2 Oct 2026: Published.