SFC /SCANNOW Command - Run in Windows 8

How to Run "SFC /SCANNOW" Command at Boot or in Windows 8 and 8.1​

   Information

The SFC command scans the integrity of all protected system files and replaces incorrect versions with correct Microsoft versions.

This tutorial will show you how to run the sfc /scannow command at boot or in Windows 8 to attempt to repair corrupted or modified system files.

   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/tap on Start, and set to Manual.

Services - Start, Stop, and Disable in Windows 8

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

If SFC is unable to repair corrupted system files because the store (source) is corrupted, then you could run the Dism /Online /Cleanup-Image /RestoreHealth command to fix Windows component store corruption, then afterwards try running the SFC scan again.

   Warning

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.

CONTENTS:

• Option One: To Run SFC /SCANNOW Command at Boot
• Option Two: To Run SFC /SCANNOW Command in Windows 8
• Option Three: How to View Only the "SFC" Scan Results from the CBS.LOG

OPTION ONE

To Run SFC /SCANNOW Command at Boot

1. Open a command prompt at boot.

2. In the command prompt, type diskpart and press Enter, then type list volume and press Enter. (see screenshot below)



3. Make note of the drive letters for your boot drive (ex: 350MB "System Reserved" partition) and Windows 8 drive, then type Exit and press Enter. (see screenshot above)
NOTE: If you do not have a "System Reserved" partition, and are not multi-booting with another operating system, then the boot drive and Windows 8 drive may be the same drive letter.

4. In the command prompt, type the command below and press Enter. (see screenshot below)
NOTE: You will see a blinking cursor at the prompt until finished. This will take a while to finish running though.


sfc /scannow /offbootdir=C:\ /offwindir=D:\windows

   Note

You will need to substitute the drive letter of the partition/volume where your system boot files are stored in the offbootdir=C: part of the command above instead.[

You will need to substitute the drive letter of your Windows 8 partition/volume in the offwindir=D: part of the command above instead.

5. When the scan is complete, hopefully you will see an all is ok message like below.




6. Close the command prompt, and restart the computer to start Windows 8.

   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 times restarting the PC after each time to completely fix everything that it's able to.

If not, then run the Dism /Online /Cleanup-Image /RestoreHealth command to repair any component store corruption, restart the PC afterwards, and try the sfc /scannow command again.

If still not, then you could do a refresh of Windows 8, or run a System Restore using a restore point dated before the bad system file occured to fix it. You may need to repeat doing a System Restore until you find a older restore point that may work.

When running SFC offline (at boot), SFC logging in the CBS.log file is not supported to be able to create a sfcdetails.txt file in OPTION THREE below.

OPTION TWO

To Run SFC /SCANNOW Command in Windows 8

1. Open an elevated command prompt or elevated PowerShell.

2. In the elevated command prompt or PowerShell, type sfc /scannow and press Enter. (see screenshot below)
NOTE: This may take a while to finish running.



3. When the scan is complete, hopefully you will see an all is ok message like the bottom screenshot below.
NOTE: Luckily SFC was able to repair my corrupted system files automatically.

   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 times restarting the PC after each time to completely fix everything that it's able to.

If not, then run the Dism /Online /Cleanup-Image /RestoreHealth command to repair any component store corruption, 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 could do a refresh of Windows 8, or 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 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 THREE

How to View 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.

When running SFC offline (at boot) in OPTION ONE, SFC logging in the CBS.log file is not supported to be able to create a sfcdetails.txt file.

1. Open an elevated command prompt or elevated PowerShell.


2. In the elevated command prompt or PowerShell, copy and paste the command below and press Enter.
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. When finished, 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:

If you have to many files that are corrupted, then run the Dism /Online /Cleanup-Image /RestoreHealth command to repair any component store corruption, restart the PC afterwards, and try the sfc /scannow command again.

If you only have a few, then you could manually extract a new copy directly from your Windows 8 installation DVD or USB thumb drive, or ISO file if in a virtual machine.

Extract Files from Windows 7 Installation DVD

That's it,
Shawn

Related Tutorials

---

• How to Refresh Windows 8 and 8.1
• How to Reset Windows 8 and 8.1
• How to Use DISM to Fix Component Store Corruption in Windows 8 and Windows Server 2012

 

[JohnnyBob]

Thanks!

I'd just like to express my appreciation for your info. I had a sfc problem with my W8.1 Pro and solved it in these forums. Here are the references which may help others too:
http://www.eightforums.com/tutorials/3047-sfc-scannow-command-run-windows-8-a.html
http://www.eightforums.com/general-...ed-access-cbs-log-file-fixing-corruption.html
http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

 

[COMPUTIAC]

If I type in type sfc /scannow will this remove anything besides the bad stuff ?

 

[Brink]

Hello Bob.

Nope. The SFC will only scan to see if you have any corrupted or modified Windows system files. If any are found, then SFC will automatically try to repair them by replacing them with a clean default copy from the component store.

Basically, no harm no foul unless you modified a system file that will be undone afterwards.

 

[COMPUTIAC]

Hello Bob.

Nope. The SFC will only scan to see if you have any corrupted or modified Windows system files. If any are found, then SFC will automatically try to repair them by replacing them with a clean default copy from the component store.

Basically, no harm no foul unless you modified a system file that will be undone afterwards.

OK then will give it a try and see what happens.

 

[COMPUTIAC]

OK ran it once. How does it look ?



This is the log:
View attachment sfcdetails.txt

 

[Brink]

You're image was broken. See if uploading and attaching the image directly here instead will work.

http://www.eightforums.com/tutorials/2598-screenshots-files-upload-post-eight-forums.html

 

[COMPUTIAC]

Ran sfc /scannow two more times and both came back clean.

 

[Brink]

Great news.

 

[ichbinrt]

Doesn't work...

So here is my problem (method 1). After I have written "sfc /scannow /offbootdir=C:\ /offwindir=D:\Windows" and hit enter, there is written "Windows Resource Protection could not start the repair service. My big problem is that my computer can't get on there is a problem. When I want to 'exit and continue to windows 8' ,there is the problem code "0xc000021a". Please help.
Ps: I have an samsung laptop series 5

In love
ichbinrt

----------------
PLEASE HELP
----------------

 

[Brink]

Hello ichbinrt, and welcome to Eight Forums.

If this is for a BSOD, then you should read the instructions below and post this in the BSOD Crashes and Debugging forum instead for better support with it.

http://www.eightforums.com/bsod-cra...e-screen-death-bsod-posting-instructions.html

 

[MitchMan]

SFC /Scannow Erorrs help me read the log file and fix

Hello,

Can anyone interpret my sfc /scannow log and tell me what's wrong. Windows seems to run smoothly but if there are windows corrupted files I would like to fix them. Here is what it says in CMD and I will attach the log file. Thank you so much.

View attachment SFC.txt

Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.C:\WINDOWS\system32>sfc /scannow
Beginning system scan. This process will take some time.
Beginning verification phase of system scan.
Verification 100% complete.
Windows Resource Protection found corrupt files but was unable to fix some
of them. Details are included in the CBS.Log windir\Logs\CBS\CBS.log. For
example C:\Windows\Logs\CBS\CBS.log. Note that logging is currently not
supported in offline servicing scenarios.
C:\WINDOWS\system32>

 

[Brink]

Hello Mitch, and welcome to Eight Forums.

You attached a copy of your full CBS.log instead of the sfcdetails.txt file from Option Three. The sfcdetails.txt will only show details of the SFC scan without all of the other unrelated information in the CBS.log.

Looking at your SFC details, it shows that it cannot repair Amd64\CNBJ2530.DPB of the prncacla.inf file due to a hash mismatch. The prncacla.inf file is part of the default Microsoft Windows printer drivers package included in Windows.

If you don't use this printer driver or not having any issues from it, then it's nothing to worry about.

Hope this helps,
Shawn

 

[MitchMan]

Thanks for moving and answering my post Shawn. I have ran Dism and it's now fixed.

 

[Brink]

Great news.

 

[Azurohn]

Hi Brink,
I followed the steps for this fix then got tripped up by this error: Windows Resource Protection Could Not Start the Repair Service
.So I followed the steps in the yellow sticky and checked that the Windows Modules Installer. It was enabled and set to manual.
When I try to run the SFC SCANNOW it still comes up with the error Windows Resource Protection Could Not Start the Repair Service.
Is it that I have the drive letters wrong? I tried a few different variations. However I'm sure that both my boot files and Windows 8 are located on C....

 

[Brink]

Hello Azurohn, and welcome to Eight Forums.

Option One is to run SFC at boot instead of in Windows. Are you able to use Option Two instead?

 

[Jarminx]

Question.. SFC/Scannow attempts to find and fix corrupt or modified system files.. Does this include the registry and any changes I've made? Basically, I made a bunch of registry changes and if running the scan resets the changes, then I will be steering clear of the scan

 

[Brink]

Question.. SFC/Scannow attempts to find and fix corrupt or modified system files.. Does this include the registry and any changes I've made? Basically, I made a bunch of registry changes and if running the scan resets the changes, then I will be steering clear of the scan

Hello Adam,

SFC doesn't affect the registry. Only Windows system files.

 

[Jarminx]

Question.. SFC/Scannow attempts to find and fix corrupt or modified system files.. Does this include the registry and any changes I've made? Basically, I made a bunch of registry changes and if running the scan resets the changes, then I will be steering clear of the scan

Hello Adam,

SFC doesn't affect the registry. Only Windows system files.

Thanks

 

[Brink]

You're most welcome.