How to Run the "SFC /SCANNOW" Command at Boot or in Windows 8

   Information

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

OPTION ONE

To Run the 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.

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





4. 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 or more times to completely fix everything that it's able to.

If 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.

OPTION TWO

To Run the SFC /SCANNOW Command in Windows 8

1. Open a elevated command prompt in Windows 8.


2. In the elevated command prompt, 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 unlike the 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 or more times to completely fix everything that it's able to.

If 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.

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 a elevated command prompt in Windows 8.


2. In the elevated command prompt, 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.

Code:

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 by extracting 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
• How to Reset Windows 8