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

 

[JRZ]

SevenForums is the best

Used the command line and followed instructions.

Found errors and corrected these.

Thanks to all of You!!!

 

[Brink]

You're most welcome JRZ, and welcome to Seven Forums.

 

[Keyoung59]

Shawn,

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

Saying can't open


Also I did a sfc/ scannow 3 times and still can't fix corrupted files. I have a problem on one of my hard drive when I click on one folder on the other hard drive it crashes explorer.exe and the other folders on there are fine. Any idea for this problem

Thanks,

Kevin

 

[Brink]

Hello Kevin,

Are you using the command in a elevated command prompt (right click on cmd.exe file -> Run as administrator)?

 

[Keyoung59]

Yes

 

[karlsnooks]

Reboot your computer into Safe Mode.
Run cmd.exe as administrator.
Now you should be able to execute the command.

 

[Brink]

In addition, you might try running SFC at boot as well.

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

 

[Keyoung59]

Reboot your computer into Safe Mode.
Run cmd.exe as administrator.
Now you should be able to execute the command.

Didn't work..

 

[karlsnooks]

You must boot into safe mode.

Go immediately to an elevated command prompt.

Navigate to C:\windows\logs\cbs

type following command:
findstr /c:"[SR]" cbs.log > sfcdetails.log

type that precisely as written.

After the command finishes,
type following command:
DIR

you should see both a cbs.log fila and a sfcdetails.log file.

 

[Keyoung59]

@Shawn: Didn't fix it.

@karlsnooks: Can't open cbs.log file in safe mode didn't work

 

[karlsnooks]

I'm not asking you to open the file.

How are you booting into SafeMode?

 

[Keyoung59]

I'm not asking you to open the file.

How are you booting into SafeMode?

F8 Then Safe Mode

Then I open command prompt as Admin

Enter this as you asked: findstr /c:"[SR]" cbs.log > sfcdetails.log

I get this message when enter that in Command Prompt "Can't Open CBS.log"

 

[cyclic]

You say 'Also I did a sfc/ scannow 3 times ' which is wrong syntax, the command is sfc /scannow. There is a space after sfc and before the slash, if you have typed it with the space after the slash, it likely wont work.

 

[Keyoung59]

You say 'Also I did a sfc/ scannow 3 times ' which is wrong syntax, the command is sfc /scannow. There is a space after sfc and before the slash, if you have typed it with the space after the slash, it likely wont work.

I just miss typed it on the post.

 

[Brink]

Kevin,

Will it let you right click on the CBS.log, click on Send To and Compressed (zipped) folder, then click OK to have it on the desktop?

If so, upload that ZIP file, and I'll see what may be in the CBS.log.

 

[Keyoung59]

Here you go Shawn. Thanks Everyone for helping hope it can be fixed.

View attachment 166052

 

[Brink]

Kevin,

From extracting the [SR] details from your CBS.log, it shows that your explorer.exe file is corrupted and cannot be repaired since the copy in the CAB file is also corrupted and a hash mismatch.

I attached a copy of your sfcdetails below.

Did you modify or replace the explorer.exe file for anything?

If you are not having any issues from this, then I wouldn't worry about it since you may have to reinstall if you really needed to fix explorer.exe.

 

[Keyoung59]

Shawn,

I don't think I have changed explorer.exe What if I did a Repair Install. Would this keep all my programs?

I did change context menu.

Repair Install:
http://www.sevenforums.com/tutorials/3413-repair-install.html

Or do you think it's better to reinstall fresh?

There is one folder that is on another drive that gives me a problem. When you select the folder it restarts explorer.exe every time. The only thing in that folder is movie files. "avi" "mp4".

Thanks,

Kevin

 

[Brink]

Yes, a repair install will be able to fix the explorer.exe file. However, be sure to read the Warning box about SP1 in the repair install tutorial. You will not be able to do a repair installed unless you either use a "retail" Windows 7 w/SP1 installation disc, or uninstall SP1 first.

 

[Keyoung59]

What if I did a "Any Time Upgrade" to Ultimate. Do I use the Home Prem. or do I need the Ultimate CD.