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've used sfc /scannow when I knew there were problems in the OS, and it never shows anything. Recently I downloaded some software that screwed up various system functions, but sfc found nothing wrong. I removed the software and used a System Restore, but this is always my experience with sfc. It's happened before.

Hello mate,

It just depends on what was affected by the software. It's not uncommon for software to break something without affecting system files.

SFC will only check for corrupted or modified system files, and then attempt to repair them by replacing them with an original copy from the component store if it's not also corrupted.

 

[RoWin7]

It was a screensaver, and although my A-V reported nothing, it screwed with my OS, and I developed 4 or 5 problems. Aren't corrupted files what causes bugs?

 

[Brink]

Aren't corrupted files what causes bugs?

Not always. It could be changes to settings, or just something the software is doing.

 

[White]

I always use this section of the forum to read again, you will need these commands.

 

[Snick]

Many times it is not corrupt files but incompatibility with other apps.
If you have to anti-virus running, not recommended, M$ version and another may conflict.
Always a good idea to backup your system to an external hard drive, if you install an app and it causes problems, reimage the drive with the backup and we are not needed to help you figure it out.
BSODs are always fun, and axe0 is usually one that can finger (typo intentional) it out.

Snick

 

[zmth]

when i did the verify only it did come up with violations and it said they are listed in...cbs.log but when i tried to bring that up it said 'Access denied'

 

[Brink]

when i did the verify only it did come up with violations and it said they are listed in...cbs.log but when i tried to bring that up it said 'Access denied'

Hello zmth,

Be sure to open an elevated command prompt when using option 3 to get the SFC details from the CBS log.

https://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html#option3

 

[zmth]

actually later from another ... i was able to open it and did get the details. And then decided to run it and just let it try and fix and did that and it replied it couldn't fix all but think it did some. As far as the original problem of not being able to remove entries from the explorer quick launch lists I got one removed from the explorer start menu for programs (though i don't think it had anything to do with running that scan fix) but i still can't get one removed from the user pinned quick launch at the top on the right side for directories lists. It says the usual 'unpin from this list' when hover with the mouse over the pin icon just to the right of the particular directory name but it does nothing- that is for the one i want to remove but it does work for all the others that i don't want to remove-i just tried it and put them back in again. Also wrt that directory i want removed when press the left mouse button get a usual " ... unavailable...have been moved.... do you want to remove it from list " message and i press yes but it doesn't remove it. Had also done a restore point from as far back as i dare go and reboot etc.etc. but still will not remove it no matter what.