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]

This is for Vista, but still applies to Windows 7 as well. It'll help explain better what it's for.

What is the WINSXS directory in Windows 2008 and Windows Vista and why is it so large? - Ask the Core Team - Site Home - TechNet Blogs

 

[Satirelol]

Hey Brink, thank you for your support here!
Here's my CBS.log file, as I there were errors Windows couldn't fix just like the user before.

CBS.log

Do you recommended reinstalling Windows 7, what are the errors here and what exactly are you looking at to find them out?

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

My scfdetails.txt in the desktop ends up being empty (0 bytes)

 

[Brink]

Hello Satire, and welcome to Seven Forums.

Did you run the sfc /scannow command?

There are no entries in your CBS.log for a SFC scan.

 

[Satirelol]

Nope I ran it a few days ago, maybe it deleted the results or something. Just reran it, here you go:

sfcdetails.txt (looks like it works now, as there's content): sfcdetails.txt
CBS.log: CBS.log

 

[Brink]

You could upload the files directly instead though.

2011-10-14 11:45:16, Info                  CSI    000002f8 [SR] Cannot repair member file [l:28{14}]"iassdo.dll.mui" of Microsoft-Windows-Networking-Internet_Authentication_Service_Iassdo.Resources, Version = 6.1.7600.16385, pA = PROCESSOR_ARCHITECTURE_INTEL (0), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2011-10-14 11:45:16, Info                  CSI    000002fa [SR] Cannot repair member file [l:28{14}]"iassdo.dll.mui" of Microsoft-Windows-Networking-Internet_Authentication_Service_Iassdo.Resources, Version = 6.1.7600.16385, pA = PROCESSOR_ARCHITECTURE_INTEL (0), Culture = [l:10{5}]"en-US", VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2011-10-14 11:45:16, Info                  CSI    000002fb [SR] This component was referenced by [l:266{133}]"Microsoft-Windows-WindowsFoundation-LanguagePack-Package~31bf3856ad364e35~amd64~en-US~6.1.7601.17514.Windows Foundation Language Pack"
2011-10-14 11:45:16, Info                  CSI    000002fe [SR] Could not reproject corrupted file [ml:60{30},l:58{29}]"\??\[B][COLOR=red]C:\Windows\SysWOW64\en-US[/COLOR][/B]"\[l:28{14}]"[B][COLOR=red]iassdo.dll.mui[/COLOR][/B]"; source file in store is also corrupted

From this, you have a corrupted iassdo.dll.mui file at the location below that cannot be fixed. If you like, you could use the tutorial below to extact a good copy of the iassdo.dll.mui file from your Windows 7 installation disc to replace the corrupted one on your current installation with.


C:\Windows\SysWOW64\en-US

http://www.sevenforums.com/tutorials/42776-extract-files-windows-7-installation-dvd.html

 

[Satirelol]

Ok I just did that, took ownership of the file so I could overwrite because at first I had a permission problem.

Reran sfc /scannnow, it's still showing the same error

 

[Brink]

Unless you are having an issue with language packs, I wouldn't worry about it though.

 

[Satirelol]

I see. Well the main reason I was using sfc /scannow is because it was recommended in order to fix an issue I was having with BFBC2. If that .dll.mui file is not related to my issue, then I guess it must be something else. Please a take look at my thread if you have time: http://www.sevenforums.com/crashes-...-battlefield-bad-company-2-a.html#post1615766

 

[Brink]

No, I don't think that file would be related to that issue.

 

[karlsnooks]

This is for Vista, but still applies to Windows 7 as well. It'll help explain better what it's for.

What is the WINSXS directory in Windows 2008 and Windows Vista and why is it so large? - Ask the Core Team - Site Home - TechNet Blogs

Shawn,
what have i done that id do not have a vsp1cln.exe on my computer:

Service Pack 1 contains a binary called VSP1CLN.EXE, a tool that will make the Service Pack package permanent (not removable) on your system, and remove the RTM versions of all superseded components.

 

[Brink]

Hello Karl,

That file is what is used to run the SP1 disk cleanup tool for Vista. Of course, Vista is on SP2 now though. The link was only to help reference what the winsxs folder is for though.


For Windows 7, you would want to use the one in the tutorial below instead.

http://www.sevenforums.com/tutorials/122262-windows-7-sp1-disk-cleanup-tool.html

 

[karlsnooks]

Shawn, thanks. I knew of the approach in the tutorial but didn't know if I had missed something.

The link did bring one question to mind:

When I delete a file for system32 folder them am I really deleting just a link to a sxs file?

 

[Brink]

No, they are not linked to the files in the winsxs folder. They are separate.

 

[ICIT2LOL]

Problem

Hiyya Shawn mate I have typed the sfc in the search > click on the highlighted result > the small black screen appears for an instant and then disappears.

Doesn't matter how many times I did this - same result - problem with my OS?

 

[Brink]

Hello John,

You would need to open a elevated command prompt first, then type sfc /scannow in the command prompt instead.

 

[popsky]

Thankyouuu

Brink,
Thank you very much for the nice, reader-friendly tutorial! I'm so glad I found this article (and forum) after spending many hours of hair-pulling and trying to figure out what was wrong with my laptop.

After checking the CBS.LOG, now I now that the termsrv.dll is corrupted, I assume that's why my laptop freezes after booting. Only the "safe mode" works. I tried running the scannow command several times, but the problem persists. Would you mind giving me some tips to solve it?

Thanks again for your help!

 

[Brink]

Hello Popsky, and welcome to Seven Forums.

The C:\Windows\System32\termsrv.dll file that is used with "Remote Desktop Sessions". If you do not do remote desktop connections, then I wouldn't worry about trying to fix the file. If you do, then you could do what's in the yellow TIP box at the bottom of the tutorial to extract the termsrv.dll file from your installation disc to replace it in your current Windows 7 installation at the location(s) specified in the sfcdetails.log file.

However, I do not believe that this is the cause of your laptop freezing up though. I would recommend that you scan your system with the free programs Malwarebytes (free) and Microsoft Standalone System Sweeper to help make sure that you system is malware/virus free. Afterwards, post all the details about your system freezing in the Crashes and Debugging forum area to see if we may be able to help with this.

 

[popsky]

Hello Popsky, and welcome to Seven Forums.

The C:\Windows\System32\termsrv.dll file that is used with "Remote Desktop Sessions". If you do not do remote desktop connections, then I wouldn't worry about trying to fix the file. If you do, then you could do what's in the yellow TIP box at the bottom of the tutorial to extract the termsrv.dllfile from your installation disc to replace it in your current Windows 7 installation at the location(s) specified in the sfcdetails.log file.

However, I do not believe that this is the cause of your laptop freezing up though. I would recommend that you scan your system with the free programs Malwarebytes (free) and Microsoft Standalone System Sweeper to help make sure that you system is malware/virus free. Afterwards, post all the details about your system freezing in the Crashes and Debugging forum area to see if we may be able to help with this.

Oh, thank you for the information and the fast reply!
I did both, replacing the "termsrv" file to the instructed folders and running the Malwarebytes Program. And you're correct! After the Malwarebytes scanned and fixed several problems in my computer, voila! It works just fine now! Now I'm running my computer smoothly, no more freezing up after booting!

Thank you very much for this, you are a livesaver, seriously.

 

[Brink]

You're most welcome Popsky. I'm very happy to hear that your computer is back up and running fine again.

 

[barbarossa2241]

I did create short cut and did a scan. "found corrupted file but not able to fix some of them". What do I need to do now ? Thanks.