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

 

[Brink]

You might see if using the DISM command in step 6 of OPTION TWO below using an ISO file as the source may be able repair the files for you.

http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

 

[computernoob407]

You might see if using the DISM command in step 6 of OPTION TWO below using an ISO file as the source may be able repair the files for you.

http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

From this thread...http://www.eightforums.com/performance-maintenance/73163-sfc-scannow-successfully-repaired.html, in post #3 and #9, that the windows update KB3022345, which I have and already uninstalled, caused some file corruption that it should be removed. My laptop doesn't have a CD drive, I have created a recovery usb boot media. Is this what you are talking about? Can this DISM command be done within windows?

 

[Brink]

Yes, the DISM command can be run from within Windows. You're basically using a downloaded Windows 8.1 ISO file as the source instead of the Windows component store to repair the files with.

 

[computernoob407]

You might see if using the DISM command in step 6 of OPTION TWO below using an ISO file as the source may be able repair the files for you.

http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

I'm slightly confused on the steps. In option 2, step 6 in the link, it says under "A" to use 'Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:Full Path to install.wim file:1'. I don't see the 'install.wim' file in the sources folder, I even search within the E usb drive and it didn't find it. I see 'install.esd, install.exe., installeventres.dll, and installprep.exe. Do I include the word 'file' in the command?

 

[derekimo]

You might see if using the DISM command in step 6 of OPTION TWO below using an ISO file as the source may be able repair the files for you.

http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

I'm slightly confused on the steps. In option 2, step 6 in the link, it says under "A" to use 'Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:Full Path to install.wim file:1'. I don't see the 'install.wim' file in the sources folder, I even search within the E usb drive and it didn't find it. I see 'install.esd, install.exe., installeventres.dll, and installprep.exe. Do I include the word 'file' in the command?

It must because of the recovery drive you created, not sure, but I would just download an ISO myself,

http://www.eightforums.com/tutorials/18309-windows-8-windows-8-1-iso-download-create.html

And about the word 'file', the answer is no, you can see the path in this screenshot I highlighted it,



The example right above it shows it also,

 

[computernoob407]

You might see if using the DISM command in step 6 of OPTION TWO below using an ISO file as the source may be able repair the files for you.

http://www.eightforums.com/tutorials/26512-dism-fixing-component-store-corruption-windows-8-a.html

I'm slightly confused on the steps. In option 2, step 6 in the link, it says under "A" to use 'Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:Full Path to install.wim file:1'. I don't see the 'install.wim' file in the sources folder, I even search within the E usb drive and it didn't find it. I see 'install.esd, install.exe., installeventres.dll, and installprep.exe. Do I include the word 'file' in the command?

It must because of the recovery drive you created, not sure, but I would just download an ISO myself,

http://www.eightforums.com/tutorials/18309-windows-8-windows-8-1-iso-download-create.html

I did download from that link, using option 1, my laptop doesn't have a cd drive and don't have a CD/DVD burner available. When I created the usb, my anti virus real time protection was on and it said it block autorun. When it was getting the usb ready or copy the files to it, the real time protection was on. So I turned it off with it staying at 0% for a couple minutes.

 

[derekimo]

Just download the ISO file, you don't need to create a USB with it or anything else, once you have that file you can just right click on it and select mount,

 

[computernoob407]

Just download the ISO file, you don't need to create a USB with it or anything else, once you have that file you can just right click on it and select mount

Thank you for assisting, I downloaded the .ISO from option 1 with "Windows Installation Media Creation Tool". I ran the DISM command and it go to a little over 40% and it gave an error: 0x800f0906, the source files could not be downloaded. Use the 'source' option to specify the location of the files that are required to restore the feature. Attached is the DISM log, but it's not showing.

View attachment dism.log

 

[Brink]

If you like, you could also try doing a repair install to fix the system files without losing anything.

http://www.eightforums.com/tutorials/26095-repair-install-windows-8-a.html

 

[computernoob407]

If you like, you could also try doing a repair install to fix the system files without losing anything.

http://www.eightforums.com/tutorials/26095-repair-install-windows-8-a.html

Are there any other options? I really don't want to lose any of my files or anything if something goes wrong. Typically how long will the repair take? My hard drive is a 5400 rpm 1 tb with approximately 200 gb used space. In the .ISO, is there a difference between windows 8.1 and 8.1 single language? It looks like I have windows 8.1 update installed because in the metro interface I see a power and search icon on the top right next to my user name.

 

[Brink]

I would always recommend to back up anything that you don't want to lost to be safe.

The repair install can vary per system on how long it may take to finish from 20 minutes to overnight depending on much data and corruption there is.

 

[computernoob407]

Update- I did a repair install and after about 2 hours, I was up and running in my desktop. I ran 'sfc /verifyonly' and it said 'Windows resource protection did not find any integrity violations'. I'm really happy! Thank you brink and derekimo, I really do appreciate your help! Now I can image my laptop using macrium and restore it on my new SSD. Hopefully the restore goes well!

 

[Brink]

You're most welcome computernoob407. I'm glad we could help.

 

[jgilbertvegas]

how about UEFI mode?

 

[Brink]

how about UEFI mode?

Hello jgilbert, and welcome to Eight Forums.

Yes, you can run a SFC scan with a UEFI installation.

 

[jgilbertvegas]

i would like to know which drive i'm going to boot time sfc /scannow?

 

[Brink]

You would want to run SFC on your Windows C: drive.

 

[jgilbertvegas]

thank you

 

[Brink]

You're most welcome.

 

[Orion0921]

Im stuck with this. does it mean that its still scanning?