System file check (SFC) Scan and Repair System Files & DISM to fix things SFC cannot

Technical Level : Basic


System file check is a utility built into the Operating System that will check for system file corruption The sfc /scannow command (System File Check) scans the integrity of all protected operating system files and replaces incorrect, corrupted, changed, or damaged versions with the correct versions where possible.  When it cannot repair the damage DISM should be run to fix as many errors as possible.

System file check works on Vista and UP

Dism works on win 7 and UP

If you are running an insider build (ie 14915) and SFC fails ~20% it is a known problem with this build

If you are running sfc &/or DISM to fix an underlying problem please tell us what that problem is!!!!


If you have modified your system files (including Windows DLL files) running sfc /scannow will revert the system files back to the default state.

It is always a good idea to back up your data beforehand!

To run a system file check (SFC)

Go to start>Type CMD

Right click and run as Administrator

(called an elevated command prompt)

If you want to verify and repair the OS type sfc /scannow (note the space between sfc and "/")

If you just want to check (verify only) the OS type sfc /verifyonly (no changes will be made using verify only)

 You may have to run this up to 3 times to fix all the problems

When you have finished it will say one of three things

Windows did not find any integrity violations (a good thing)

Windows Resource Protection found corrupt files and repaired them (a good thing)

Windows Resource Protection found corrupt files but was unable to fix some (or all) of them (not a good thing)  If you get this message run DISM as described below

If SFC was not able to repair some or all of the files there are a few options including a repair install from the OS dvd, and DISM (win 8 & UP)

If SFC did not find any violations it is still a good idea to run DISM Restorehealth


If you are on win 8 (and up) you  should also run DISM whether SFC found errors or not!!

From an elevated command prompt 

You can run Check, then Scan, but you should always run RESTORE HEALTH

To check the health (You would use /CheckHealth to only check whether the image has been flagged as corrupted)

run Dism /Online /Cleanup-Image /CheckHealth

To scan the health use /ScanHealth to scan the image for component store corruption. This option does not fix any corruption.

run Dism /Online /Cleanup-Image /ScanHealth

To RESTORE health (recommended)

Use DISM /Online /Cleanup-Image /RestoreHealth to scan the image for component store corruption, perform repair operations automatically, and records that corruption to the log file.  This generally takes 15-30 minutes depending on the corruption and size of the partition

You can run scanhealth & restore health at the same time like this

DISM.exe /Online /Cleanup-image /Scanhealth && DISM.exe /Online /Cleanup-image /Restorehealth

Type DISM /Online /Cleanup-Image /RestoreHealth .  (please note the space after "dism", & "online" & "image")
If the repair is successful you may want to re-run SFC just to check.

After running DISM it is a good idea to re-run SFC /scannow to make sure all the issues were fixed.

If you get the error message "cannot find source files"you need to have an ISO file mounted and need to specify where it is located with the below command

The ISO must be exactly the same version as the running OS.  An ISO of 10586.0 will not repair a running system of 10586.35 because it has additional updates and files.

DISM /Online /Cleanup-Image /RestoreHealth /source:WIM:X:\Sources\Install.wim:1 /LimitAccess  Where "X" is the drive letter where the ISO is located.  Simply change the "X" to the correct drive letter

If you do not have an ISO you can make one.  The instructions are here

If this wiki has proved helpful please click me too at the bottom of the wiki.

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Co-Authored JMH3143/ ZigZag3143

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Bu ileti veya öneriler size yardımcı olduysa “Yanıt olarak işaretle” linkine tıklatınız.

Tested on two Windows 10 9926 (Enterprise - upgrade from 9879 then clean install) on my Dell M4700

SCF /SCANNOW always stop after 2 or 3%

DISM /Online /Cleanup-Image /RestoreHealth always report that the sources can't be found
Tried to use /source:x:\sources\sxs /limitaccess but this folder is mostly empty on the Win10 DVD
Tried to use /source:wim:x:\sources\install.wim:1 /limitaccess --> Same problem sources can't be found


Both SFC & DISM can be made to work if you follow the above modified instructions for win 10 (10041 included)

Cat herder
Windows Insider MVP
MVP-Windows and Devices for IT
omg thank you so much for the info, i start to freak out.. in windows 10 found me almost all are corupted, with finnaly repairing some WindowsDefender dll's. But i was like ****, what im doing now, my whole windows is corupted until i read that are a lot of falses

Verify and Repair Transaction completed. All files and registry keys listed in this transaction  have been successfully repaired


No todo lo que brilla es oro.

It was our pleasure.

Thanks for letting us know that all is well.

Safe web surfing!

Microsoft MVP.
Windows Consumer Apps,
Windows Experience,
Windows Insider. it appears.
Good info, works as described, at least on 8.1.  Very helpful IF you read and follow all steps.

I have been unable to update to Win10 10074, sfc returned an error but was unable to repair, the mounting of the 10061 iso(my current build) fixed the issue.

Thank you!

Привет ZigZag3143!
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Last updated October 21, 2020 Views 3,666,206 Applies to: