SFC /SCANNOW Command - System File Checker

How to Repair Windows 7 System Files with System File Checker​

   Information

The sfc /scannow command (System File Checker) scans the integrity of all protected Windows 7 system files and replaces incorrect corrupted, changed/modified, or damaged versions with the correct versions if possible.

   Tip

If you get the Windows Resource Protection Could Not Start the Repair Service error when trying to run SFC, then make sure that the Windows Modules Installer service is enabled, click on Start, and set to Manual.

Services - Start or Disable

OR

Copy and paste the command below in the elevated command prompt, and press Enter. After the Windows Modules Installer service has started, try running the SFC command again

net start trustedinstaller

   Note

The KB3022345, KB3035583, and KB3068708 updates will cause SFC to give you a false mismatch message in SFC for files related to these updates.

You can safely ignore these results in your SFC details since it will not affect SFC from being able to repair other system files.

   Warning

Be aware that if you have modified your system files as in theming explorer/system files, running sfc /scannow will revert the system files such as explorer.exe back to it's default state. Make the appropriate backups of your system files that you have modified for theming if you wish to save them before running sfc /scannow.

:note: For the updated Windows 10 tutorial, please see - SFC Command - Run in Windows 10 - Windows 10 Tutorials

CONTENTS:

• Option One: To Run the SFC /SCANNOW Command at Boot
• Option Two: To Run the SFC /SCANNOW Command in Windows 7
• Option Three: How to See and Read Only the "SFC" Scan Results from the CBS.LOG

OPTION ONE

To Run the SFC /SCANNOW Command at Boot

1. For how, see METHOD TWO at this link: SFC /SCANNOW : Run in Command Prompt at Boot

   Note

Using OPTION TWO below is recommended if able.

If you would like to get help with your SFC issue, then be sure to upload and attach your sfcdetails.txt file from OPTION THREE below in your post.

OPTION TWO

To Run the SFC /SCANNOW Command in Windows 7

1. Open an elevated command prompt or an elevated PowerShell, and do step 2 or 3 below for what type of scan you would like to run.


2. To Scan and Repair System Files
NOTE: Scans the integrity of all protected system files and repairs the system files if needed. Please see red WARNING box at the top of this tutorial.
A) In the elevated command prompt, type sfc /scannow, press Enter, and go to step 4 below. (see screenshot below)
NOTE: This may take a little bit to finish.


3. To Only Verify if the System Files are Corrupted
NOTE: Scans and only verifies the integrity of all proteced system files only. This command will not change your system files as in the red WARNING box at the top of this tutorial.
A) In the elevated command prompt, type sfc /verifyonly, press Enter, and go to step 4 below.
4. When the scan is complete, hopefully you will see all is ok like the screenshot below.

   Note

• If SFC could not fix something, then run the command again to see if it may be able to the next time. Sometimes it may take running the sfc /scannow command 3 or more times to completely fix everything that it's able to.
• If not, then download and run the 32-bit (x86) or 64-bit (x64) System Update Readiness Tool for your same installed 32-bit or 64-bit Windows 7, restart the PC afterwards, and try the sfc /scannow command again.
• If still not, then try using OPTION ONE above to run the sfc /scannow command at boot.
• If still not, then you can attempt to run a System Restore using a restore point dated before the bad file occured to fix it. You may need to repeat doing a System Restore until you find a older restore point that may work.
• If still not, then you can use the steps in the TIP box in the OPTION THREE section below to manually replace the files that SFC could not fix if there are not to many fix.
• If there are to many files to manually fix, or you prefer not to use OPTION THREE below, then you could do a repair install without losing anything.

If you would like to get help with your SFC issue, then be sure to upload and attach your sfcdetails.txt file from OPTION THREE below in your post.

5. When done, close the elevated command prompt.

OPTION THREE

How to See and Read Only the "SFC" Scan Results from the CBS.LOG

   Note

When SFC runs, it logs it's actions into the C:\Windows\Logs\CBS\CBS.log. The steps in this option will show you how to see only the specific SFC entries with the [SR] tags in this CBS.log. This can be helpful to show you what files SFC could not fix automatically if you wanted to try and manually replace them.

1. Open an "elevated command prompt" (right click -> Run as administrator).

2. In the elevated command prompt, copy and paste the command below, and press Enter. (See screenshot below)
NOTE: This will place a sfcdetails.txt file on your desktop with only the SFC scan result details from the CBS.LOG in it.

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

3. Close the elevated command prompt.

4. Open the sfcdetails.txt file on your desktop to see the SFC scan details in the CBS.LOG.

5. You can safely delete the sfcdetails.txt file afterwards if you like.

   Tip

If you need to replace a corrupted system file that SFC cannot fix, then this will show you how to by extracting a new copy directly from your Windows 7 installation DVD.

Extract Files from Windows 7 Installation DVD

That's it,
Shawn

Related Tutorials

---

• How to Run the System File Checker in a Command Prompt at Boot
• How to Do a System Restore in Windows 7
• How to Do a Repair Install to Fix Windows 7
• How to Run Disk Check in Windows 7
• How to See Windows 7 Reliability and Problem History with Reliability Monitor
• How to Extract Files from the Windows 7 Installation DVD
• How to Troubleshoot a Problem by Performing a Clean Startup in Windows 7 or Vista

 

[Brink]

I'm not sure it will work with a "Anytime upgrade", but you would have to use a same retail installation disc as what you currently have installed.

Ultimate 64-bit in your case if you uninstalled SP1.

Be sure to backup anything that you do not want to lose first in case it doesn't work though.

 

[Keyoung59]

Ok Thanks for all the help.

 

[Brink]

You're welcome Kevin. Please let us know how it went.

 

[Keyoung59]

Shawn,

Could I try this to fix the problem?

http://www.sevenforums.com/tutorials/42776-extract-files-windows-7-installation-dvd.html

 

[Brink]

Kevin,

The problem is that the explorer.exe file will be in use, and cannot be replaced while running Windows 7 with explorer running in it.

For the amount of trouble it would take to extract the file and copy/replace it from outside of Windows, it would probably be easier to just reinstall.

 

[Keyoung59]

Ok thanks, I will try the "Repair Install" w/the Anytime Upgrade and let you know about it once I get around to it. Will post the out come on the Repair Install thread.

Thanks,

Kevin

 

[stasioau]

Hi,
Was running sfc.scannow. More or less my corrupted files been corrected.
There is one small thing. How I can back to sound when Windows was start before sfc "operation"? I have .wav file and know that this sound is located in imageres.dll folder.
Will appreciate help
Regards

 

[Brink]

Hello Stasioau,

If you mean the startup sound, then it was restored to default since a SFC /SCANNOW command undoes all modifications to system files and restores them to default. You will just need to do the tutorial below again to change the startup sound again.

http://www.sevenforums.com/tutorials/63398-startup-sound-change-windows-7-a.html

Hope this helps,
Shawn

 

[stasioau]

Hi Shawn. Just come back to my computer and see message from you. Thank you very much; I am sure that your tutorials solve my small problems.
Please accept my best regards,
stasioau

 

[Brink]

You're most welcome Stasioau.

 

[stasioau]

Thanks Shawn for all your information what you created in your tutorials. Solve my problem very easy.
One small think. Cannot get System Recovery Option, prompt, using F8. Have to use my Windows System Restore Disk. Any idea why F8 does not like me?
Best regards
stasioau

 

[Brink]

You're most welcome Stasioau.

Either way works just as well, but you have to tap F8 at and during a very limited time period while restarting. It can be difficult to get it right. I usually find it best to keep tapping F8 as soon as the computer restarts for it to be easier to do.

 

[fibercarbon]

this isnt helping.. ive ran sfc /scannow on my wind 7 64bit with Admin elevated command prompt and when its 100% done it says files could not be repaired..ive done it like 5 times and still gives same error.. attached a screenshot. i even tried doing the f8 then repair my computer and it didnt fix ? computer seems to be running ok i just know that there must be corrupted files and would like to fix them to prevent any crashing.. i do notice that when my pc starts up it sits are the starting windows screen with the windows logo like 10% loaded for like 3 minutes and then finally boots up.. this is a very fast machine gateway fx6801-03
intel core i7 920
9gb ram
64 bit..

i know a clean isntall would be the best route but im sure there has to be a way to repair whatever files are corrupt.. if not microsoft needs to make a tool that acutally repairs corrupt files!! lol rb:
please help !! thanks

cbs log is attached.. thanks in advance!

 

[Brink]

Hello Fibercarbon, and welcome to Seven Forums.

There's no guarantee that it will always be able to fix them. Could you post back and upload your sfcdetails.txt file from OPTION THREE in the tutorial to see what files it is not able to fix? From there, we will be able to see what your options may be on possibly manually fixing them.

 

[fibercarbon]

Hello Fibercarbon, and welcome to Seven Forums.

There's no guarantee that it will always be able to fix them. Could you post back and upload your sfcdetails.txt file from OPTION THREE in the tutorial to see what files it is not able to fix? From there, we will be able to see what your options may be on possibly manually fixing them.

sure no problem. thanks for the fast reply buddy. here you go!

this just puzzles me that windows hasnt made a better tool to check and repair corrupt files other than this dos tool... because chkdsk doesnt fix these issues..

 

[Brink]

Fibercarbon,

Good news is that none of them are critical system files. They are only corrupted sample images, videos, and music files in a few of the C:\Windows\winsxs\amd64_microsoft-windows.......... CAB folders, and should not affect the performance of Windows 7 since they are only samples. SFC cannot fix these since these are the CAB files that SFC would normally use to fix/replace them from.


EDIT:
Chkdsk only attempts to repair bad sectors on the HDD and does not repair corrupted files, so it's impossible for it to fix these files.

 

[karlsnooks]

Check Disk (chkdsk) is checking the disk for defective areas, regardless of the type of info stored in the bad area.

SFC is checking the system files. A file can be corrupt and located on a perfectly sound area on the disk.

 

[fibercarbon]

Fibercarbon,

Good news is that none of them are critical system files. They are only corrupted sample images, videos, and music files in a few of the C:\Windows\winsxs\amd64_microsoft-windows.......... folders, and should not affect the performance of Windows 7 since they are only samples.

that folder is like 12gb full of a ton of folders? what is it ? i dont have anything amd on my pc that im aware of.. nvidia graphics.
can i delete that folder?

thanks for the help and Reps given!

 

[Brink]

No, do not delete any of the folders or files in the C:\Windows\winsxs folder. If you do, you will most likely be having to reinstall Windows 7 shortly after.

 

[fibercarbon]

No, do not delete any of the folders or files in the C:\Windows\winsxs folder. If you do, you will most likely be having to reinstall Windows 7 shortly after.

what are all these used for seems like 11gb of junk at first glance? lol