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

 

[Spartacii]

Hello. Attached is my sfcdetails.txt file. Iam not sure how to read it. It looks to me that the only "corrupted" files are windows fonts but I am note sure. I did uninstall many windows fonts that I will never use. If that is all there is then I would think I am okay. Can someone take a look at the file and let me know if I haveto do a repair? Thanks.

 

[Brink]

Hello Spartacii,

It looks like SFC had found and repaired some corrupted fonts, but you're good to go now.

 

[glnz]

brink - I've forgotten what is recommended for Win 7 like DISM that works in Win 10 (but not 7). Can't find it. The Win 7 command is related to an image command.
Please re-post that command. Thanks.

 

[Brink]

Hello glnz,

Here you go.

https://support.microsoft.com/en-us/kb/947821

 

[mobilebyrd]

I ran SFC 4 times in a row and it wasn't able to fix all issues.
I attached the sfcdetails.txt file in case someone is willing to help me troubleshoot the issues.
Thanks in advance.

 

[Brink]

I ran SFC 4 times in a row and it wasn't able to fix all issues.
I attached the sfcdetails.txt file in case someone is willing to help me troubleshoot the issues.
Thanks in advance.

Hello mobilebyrd, and welcome to Seven Forums.

You have the Windows 7 update (KB3022345) causing corrupt files issue. The link below can help show you how to fix this.

The Tech Cookbook – Windows 7 update (KB3022345) causing corrupt files

 

[torchwood]

3022345

Hi Mobilebyird,
Follow this link same problem.

http://www.sevenforums.com/windows-updates-activation/392642-windows-update-error-code-643-a.html

Roy

You beat me Brink

 

[mobilebyrd]

Thanks Brink. I'm creating a restore point before attempting the repairs outlined in your link. I'll report back once I'm done.

 

[mobilebyrd]

Thank you both for your replies.
I followed the steps as outlined on the other page and the last scan came back with no errors.
Once again, thank y'all very much.

 

[Brink]

You're most welcome. Glad we could help.

 

[mobilebyrd]

The corruption is back...
I attached today's SFCDetails which has some familiar lines in it.

I'm open to any suggestions as I need a stable machine.

 

[Brink]

It appears to be from the KB3022345 update. If you're not having any issues other than what SFC is reporting, then you could safely ignore it until hopefully a new update will fix it.

 

[Lawsonhk]

Hi, when I open OUTLOOK, the computer often frozen and become non-responsive for more than 15 minutes. Thought it seems ok when I use OUTLOOK (safe mode). I check the Event Viewer, it seems like it is due to an Error: Event ID 481 Source: ESENT
"Windows (5688) Windows: An attempt to read from the file "C:\ProgramData\Microsoft\Search\Data\Applications\Windows\Windows.edb" at offset 170033152 (0x000000000a228000) for 32768 (0x00008000) bytes failed after 319 seconds with system error 1117 (0x0000045d): "The request could not be performed because of an I/O device error. ". The read operation will fail with error -1022 (0xfffffc02). If this error persists then the file may be damaged and may need to be restored from a previous backup."


I tried chkdsk /f already. But I am still having problem after it has successfully completed.

Then I tried using sfc /scannow, it stopped at around 42% and showing the error message "windows resource protection could not perform the requested operation". I tried to run sfc /scannow again while login the Windows in safe mode (by pressing F8), but it also stopped at 42% and showing the same error message.

What should I do now? Thanks a lot for your help in advance!

 

[Brink]

Hello Lawson, and welcome to Seven Forums.

You could 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.

 

[Lawsonhk]

Hello Brink,

Thanks for your prompt reply and help. However, after I installed the System Update Readiness Tool, when I run the sfc /scannow, it still stops at 42% with the same error message of "Windows Resource Protection could not perform the requested operation."

What would you now suggest me to do? Thanks in advance.

 

[Brink]

If you haven't already, see if you may have any luck running SFC in a command prompt at boot.

 

[Lawsonhk]

Hello Brink, sfc finally went all the way to 100% after chkdsk /x /f /r. But some files seems still unable to fix. I have attached the sfcdetails. Could you please help take a look? Many thanks.

 

[Brink]

Lawson,

It shows that there's a hash mismatch for the mcmde.dll file. This is from Media Center.

If you tried to add Media Center to Windows 10, then this would be why you are seeing this since Media Center is no longer a feature included in Windows 10.

 

[Lawsonhk]

Thanks for your reply. But I am using Windows 7. Would this be a problem?

 

[Brink]

Sorry, I was thinking Windows 10 for some reason. If you don't use Media Center or don't have any issues with Media Center, then it's nothing to worry about.