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

 

[bagavan]

Ran the scan, but when I went to C:WINDOWS\logs\cbs, I couldn't open the CBS text file. I got a message "Access Denied". Say what?

copy the cbs log and paste into some other location.

By doing this you can open the log.

 

[djbillyd]

I do believe you're right. I have done the repair install. I am updating as we speak. I'll let you know what happens next!

 

[djbillyd]

"SFC /SCANNOW Command - System File Checker" update

I did all of that, all of the scans, the repair install, all of it, and just now, I clicked on "Computer" and Windows explorer is still trying to open. I clicked off of that, and on to the system folders icon in the taskbar..., same thing. What the heck is going on? Is there a hardware glitch that can cause this? I have never had this problem before. I have had programs that won't install, programs that install and won't open, and a bunch of other problems. If I couldn't fix the problem, I could find a solution. What is this? What IS this?

 

[Brink]

Billy,

I'm not sure what the issue may be, but you might consider starting over fresh with a clean install of Windows 7 instead.

 

[djbillyd]

ERRRGGGGHHHHH!!!!! I have been dodging that like the plague! But you're probably right. I ran the scans again after posting my last comment, and got a clean bii of health. I am really wondering about my HDD now. Or even the RAM. I don't know. I'll see how long it lasts, and go from there...

Thank you so much for your assistance.

 

[Debra1533]

Read Only the "SFC" Scan Results from the CBS.LOG did not work

I exactly followed your instructions from your SFC /SCANNOW Command - System File Checker page. I copied and pasted at the elvated command prompt,as instructed. I opened up th3e text file at Desktop and it is blank. I have been struggling with my [Dell 1520 running Win 7 54bit] laptop crashing. Somewhere something is corrupted. I have checked using CCleaner, Vipre and Malwarebytes and one thing I did do was to update bios from 0 to ver 7. Any ideas or advice what I may do next? Win 32 was loaded first and then, Win 64bit.

From crashing I was able to start laptop then on the "problem" menu I chose from "Start Normally or Restore to Earlier" and am working from there.

Thank you Debra1533

 

[Brink]

Hello Debra,

Did you run the SFC /SCANNOW command in Windows prior to trying OPTION THREE?

 

[Debra1533]

Actually I was first interested in checking for existing errors prior to the scan and that's why I selected to do #3 before scanning as I was worried about losing something in the scan....I read your warnings and it concerned me. I have one 8gig memory stick and used that to back up my laptop using Win Backup program. This was done before all the crashing started. Worried that if I run scan that can delete or change things I may lose something important before realizing what's been corrupted first. I appreciate any advice; thanks so much Debra1533

 

[Brink]

Ah, ok. That's why the sfcdetails.txt file is empty since you haven't run SFC to have any entries in your CBS.log file to extract from.

The SFC scan isn't going to hurt your system. The only thing you do need to keep in mind is if you have modified any system files, then they will also be restored to default.

 

[Debra1533]

Considering all I have said about Win running on previous working version; what should I really be concerned about losing that's ciritcal or may effect (cause future crashes - which is what I'm trying to avoid?) I'm unable to conceive of what may be deleted and so much has gone on in the way of scans and fixes (Ccleaner, Malwarebytes & Vipre) what might I want to back-up or copy first? Thanks Just trying not to have more troubles as before I started this. Debra 1533

System files is so broad I can;t wrap my head around what changes I could have possibly made.. any ideas of avergae changes programs may have made and how do I know what to restore later?

I am hoping that a Win Back-up will prevent any future problems that I can restore if need be. I am performing the Back up now and will await a reply from you before I do the SFC Scan Thanks Debra1533

 

[Brink]

No worries. It's not going to damage your system. The SFC scan is designed to try and repair any corrupted or modified system files it finds back to a default state.

System files are not settings, so unless you used a program like Resource Hacker to modify a system file, then you have nothing to worry about.

If you like, you could create a restore point before running the SFC scan. This way if it undoes anything you don't want undone, you could do a system restore using the restore point to undo what the SFC scan did.

 

[Debra1533]

thanks SO MUCH just the info I needed. In much appreciation and Merry Christmas or Happy Hanukah! Debra1533

 

[Debra1533]

My SFC scan came out clean. Since this was done as a result of recent crashes; I was a bit worried about logging out then in to create this same scan to the boot bios. Is this recommended for someone who's having crashes? If you read earlier there's no problems from CCleaner, Malwarebites and Vipre. Thanks Debra1533

 

[Brink]

You're welcome Debra.

I hope you have a Happy Holidays as well. Thank you.

Since this is involving your computer crashing, you should see the link below, then post the needed information in the Crashes and Debugging forum area. We'll be happy to see what we can do to help.

http://www.sevenforums.com/crashes-debugging/96879-blue-screen-death-bsod-posting-instructions.html

 

[djbillyd]

What when you get the reply "Windows Resource Protection could not start the repair service"?

 

[Brink]

Hello Billy,

Check to see if using the yellow TIP box at the top of the tutorial may be able to help with this error.

 

[djbillyd]

It was useless for this. After I ran the scan, and got that message, I also did a "FixNCR" on it and it just cleaned up it's act. I hate it when it does that! Now, I'll just sit around looking and waiting for it to do something again! Sux...

 

[Brink]

Hopefully it won't get another error again.

 

[djbillyd]

Hopefully...

Thanks for your help. I get a lot of experience in a lot of other areas.

 

[djbillyd]

I think it probably will. I am one who expect quirps. I just hope I can learn to resolve the problems. That's what makes it fun for me!