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

 

[gilljerr88]

View attachment sfcdetails.txt
Thanks for the quick response. sfcdetails.txt attached.
Jerry

 

[Brink]

The few files that can't be repaired are related to Microsoft-Windows-Unified-Telemetry-Client from the KB3022345 update.

You can uninstall the KB3022345 Windows Update. When finished, check for any new updates and install.

http://www.sevenforums.com/tutorials/24373-windows-update-uninstall-update.html

Are you having any issues from this other than SFC not being able to repair the files?

 

[gilljerr88]

Mission accomplished

Thanks, that did the trick.
Uninstalled the KB3022345 update and reran sfc /scannow. It now runs with no problems found at all.
I've noticed no other problems, unless the inability to run SURT counts.
I expect to reinstall the KB3022345 update if update tells me it is still needed and rerun scannow. If the problem repeats I'll get back on this thread.

FYI some background. I only ran scannow because Kaspersky told me I had acquired some "unprocessed objects - legal software that can be used to hurt your computer" . Elimination required what Kaspersky called "Advanced Disinfection" multiple times. As I emerged from that, there were messages telling me that several .dll files were " not designed to operate with windows or were corrupted". An HP tutorial had told me about scannow as a recovery from corrupted windows files and so I ran it. It must have fixed most of the problems but left those last two that you have helped me with. Thanks again.
Jerry

 

[startledmoosen]

Hi guys,

So I've been experiencing crashes to black or blue screen once or twice a day for the past while. Running a sfc scan 4 or 5 times as you suggest found that there were corrupt files and that not all of them could be repaired. I went through the blue box for option three and tried all the steps (Except the repair install as I do not have a Windows disc and system restore as, for whatever reason, my pc was not making regular restore points as I assumed it would have been). Unfortunately, however, the sfc scan still shows corrupt files and the crashes persist.

I was wondering, then, if anybody wouldn't mind having a look through my sfcdetails.txt and giving me some tips as to how I might go about replacing the corrupt files manually.

Thanks a heap
Tom

 

[AddRAM]

Did you remove the update Brink listed above ?

The update causes a false corruption reading in sfc, this has been going on for months.

 

[startledmoosen]

Yep AddRAM, I noticed those posts just as I posted. Reinstalled the update and just ran an sfc and no more corruption readings. I guess my crashes, then, are unrelated but it's good to have ruled this out.

Thanks again
Tom

 

[fergiet]

Hi Guys, ran sfc and some files corrupted. Looked at log but it is double dutch to me. If someone has time to have a look it would be a great help.

Text file in dropbox https://www.dropbox.com/s/wl01n8hn6iuostg/CBS.log?dl=0

thanks.

 

[Brink]

Hello Fergiet,

You're fine. It just a false positive for the KB3068708 update file mismatch issue. No need to do anything.

 

[fergiet]

Thanks for the help. The log files were no help to me.

 

[Somuch2learn]

How do you know which update is causing corruption?

Brink, Thanks for being such a great and understandable resource. I have run sfc and gotten the attached .txt file. How can you tell which update is causing a corruption or false reading? Do I need to take action on the corruptions sfc has detected. My Windows 7 OS seems to be doing its job. Best regards.

 

[Brink]

Hello Somuch2learn, and welcome to Seven Forums.

From you log file, it's the KB3068708 update for the same false mismatch issue. Nothing needs to be done.

 

[Somuch2learn]

Brink, that's reassuring. Thanks for your reply

I noticed that today you addressed the upgrade to Windows 10 in a separate message. Will the W10 OS installation have the effect of debugging my OS, only making even better? I've had some errors (Windows can't update... code: 80070003) while trying to install "optional" updates to W9.

You have a gift for clear and concise communication. Thanks again.

 

[Brink]

Upgrading to Windows 10 should sort it since you'll be installing a new Windows.

 

[lehnerus2000]

MS needs to fix this ...

Hello Somuch2learn, and welcome to Seven Forums.

From you log file, it's the KB3068708 update for the same false mismatch issue. Nothing needs to be done.

MS needs to fix this false positive issue.

SFC is a great tool in Windows.
I have no idea how you confirm the validity of system files in Linux.

 

[Somuch2learn]

sfc /scannow vs. Windows Update

Despite Brink's suggestion that I didn't need to do anything about Update KB3068708, I uninstalled it along with KB3022345 (based on a tip from another WSF thread). I then ran sfc /scannow and got a clean bill of health. This morning Windows Update automatically re-installed KB3068708. Just for grins I re-ran sfc /scannow and got the dreaded "Windows Resource Protection found corrupt files but was unable to fix some of them." This time I will follows Brink's suggestion and do nothing abut Windows 7. After all, later this month we can all start a new learning curve with Windows 10. Good luck out there.

 

[AddRAM]

You have to tutn off auto update.

 

[NoelDP]

According to MS, these errors are perfectly normal, and can be ignored...

2015-07-03 16:36:01, Info                  CSI    00000511 [SR] Repairing 1 components
2015-07-03 16:36:01, Info                  CSI    00000512 [SR] Beginning Verify and Repair transaction
2015-07-03 16:36:01, Info                  CSI    00000514 [SR] Cannot repair member file [l:24{12}]"utc.app.json" of Microsoft-Windows-Unified-Telemetry-Client, Version = 6.1.7601.18869, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2015-07-03 16:36:01, Info                  CSI    00000516 [SR] Cannot repair member file [l:66{33}]"telemetry.ASM-WindowsDefault.json" of Microsoft-Windows-Unified-Telemetry-Client, Version = 6.1.7601.18869, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, hash mismatch
2

They are the result of MS not actually following their own rules, and tagging the relevant files in the update as 'static' rather than 'variable'.

You can either:
1) Uninstall the related update(s) KB3068708 and KB3022345 - and then hide them to prevent reinstall before MS produce a fixed version
or
2) ignore them.

There are no other significant errors in the uploaded file.

 

[marsmimar]

According to MS, these errors are perfectly normal, and can be ignored...
They are the result of MS not actually following their own rules, and tagging the relevant files in the update as 'static' rather than 'variable'.

You can either:
1) Uninstall the related update(s) KB3068708 and KB3022345 - and then hide them to prevent reinstall before MS produce a fixed version
or
2) ignore them.

There are no other significant errors in the uploaded file.

Noel, I think your option one is the best course of action. If someone merely ignores the updates, runs SFC and gets the "Windows Resource Protection found corrupt files but was unable to fix some of them" notice, there's no easy way to know if the corrupted files are due to the updates or some other system files being corrupted.

I think Microsoft owes it to consumers who are running Windows 7 to correct this issue.

 

[NoelDP]

I totally agree - especially since these two updates are far from being 'critical'!

 

[Jesse Williams]

How do I find out which files are corrupt, and how to fix them?