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

 

[Carol A]

Hi Brink:
I have been on all sorts of forums trying to find an answer. I have tried to do the scannow, but it says there is a system repair running. It will re-boot but then go right back to that page. Can't extract files from the original Windows disk, since I can't access anything but the system repair - I am on another computer now. No safe mode, nothing! At wit's end!

 

[jloc]

I'm trying to open the CBS log that was created and it keeps telling me 'Access Denied' but the file is 16.2mb so it obviously has something inside it.

 

[Brink]

Hi Brink:
I have been on all sorts of forums trying to find an answer. I have tried to do the scannow, but it says there is a system repair running. It will re-boot but then go right back to that page. Can't extract files from the original Windows disk, since I can't access anything but the system repair - I am on another computer now. No safe mode, nothing! At wit's end!

Hello Carol, and welcome to Seven Forums.

You might see if you may be able to run a sfc /scannow command in a command prompt at boot.

http://www.sevenforums.com/tutorials/139810-sfc-scannow-run-command-prompt-boot.html

Hope this helps,
Shawn

 

[Brink]

I'm trying to open the CBS log that was created and it keeps telling me 'Access Denied' but the file is 16.2mb so it obviously has something inside it.

Hello James,

You should be able to use OPTION THREE in this tutorial to create a sfcdetail.txt file that will only have the SFC scan results for this.

 

[jloc]

I'm trying to open the CBS log that was created and it keeps telling me 'Access Denied' but the file is 16.2mb so it obviously has something inside it.

Hello James,

You should be able to use OPTION THREE in this tutorial to create a sfcdetail.txt file that will only have the SFC scan results for this.

Thanks, I really need to start reading the whole thread before replying

 

[Brink]

LOL

 

[jloc]

LOL

It 'repaired' explorer.exe when the only thing it actually did was remove my custom start button

 

[Brink]

That would be correct. A sfc /scannow command will attempt to repair and replace corrupted or modified system files with a clean default one.

 

[jloc]

That would be correct. A sfc /scannow command will attempt to repair and replace corrupted or modified system files with a clean default one.

There wasn't anything else corrupted as i've just done a clean install of Windows 7

Edit: 150 posts!

 

[Brink]

...but it was "modified" (custom start button), thus repaired by restoring the file to default.

 

[jloc]

...but it was "modified" (custom start button), thus repaired by restoring the file to default.

So sfc just replaces any corrupt (or modified) files? Nice

 

[Carol A]

Didn't work - went right back to startup repair...

And thanks for the welcome! Forgot my manners

 

[Brink]

Carol,

Go ahead and run startup repair, up to 3 times if needed, to see if it will start into Windows afterwards. If not, then see if the tutorial may be able to help.

http://www.sevenforums.com/tutorials/139576-startup-repair-infinite-loop-recovery.html

 

[Carol A]

Thanks for your help, but that didn't work either. Doing a re-install now
Glad I backed up!

 

[Brink]

You're welcome Carol. I hope it goes smoothly for you.

 

[garry626]

Hi,
New to this forum and obviously here as I have snags. Running windows 7 home premium or should I say trying to! Both Windows explorer and Internet explorer move at a snails pace most of the time showing (not responding) the displayed page turns white when not responding as does the task bar following start up. Have tried sfc /scannow as described above but it only completes 2% and then states it cannot complete the task, tried this operation about 12 times but no luck. Any advice please.

 

[ICIT2LOL]

Hi,
New to this forum and obviously here as I have snags. Running windows 7 home premium or should I say trying to! Both Windows explorer and Internet explorer move at a snails pace most of the time showing (not responding) the displayed page turns white when not responding as does the task bar following start up. Have tried sfc /scannow as described above but it only completes 2% and then states it cannot complete the task, tried this operation about 12 times but no luck. Any advice please.

Hiyya Garry welcome to SF and I have to say I am no great expert mate but it would be helpful to have a few system specs posted.

Try the tutorials and type in "how to run scannow" in the search bar when it comes up - tuts are real helpful as I found them when I first joined - good luck!

Ooops just seen I am on the end of it

 

[Brink]

Hi,
New to this forum and obviously here as I have snags. Running windows 7 home premium or should I say trying to! Both Windows explorer and Internet explorer move at a snails pace most of the time showing (not responding) the displayed page turns white when not responding as does the task bar following start up. Have tried sfc /scannow as described above but it only completes 2% and then states it cannot complete the task, tried this operation about 12 times but no luck. Any advice please.

Hello Garry, and welcome to Seven Forums.

If you have not already, you might see if you may be able to do OPTION ONE in the tutorial to run SFC at boot.

 

[garry626]

Hi Brink,
THANKS TRIED OPTION AND RAN SFC AT BOOT BUT NOT CHANGE TO MY PRESENT ISSUES.

 

[Brink]

Garry,

Just to be safe, do a full scan of your system with Malwarebytes free to help make sure that your system is clean.