SFC /SCANNOW : Run in Command Prompt at Boot

How to Check / Repair the Windows System Files from a Command Prompt at Boot​

This shows how to start the PC and open a command prompt at boot so the Windows system files can be checked and repaired if possible, if the PC will not start to Windows normally or in safe mode.

   Note

For those that are dual/multi booting or if the Windows Recovery Environment (WinRE) does not 'see' the Windows Operating System needing repair, see Method Two below.

Let's get started!

In the BIOS set the boot order to boot first from the CD/DVD Drive, insert the Windows full version installation DVD or a created repair CD and restart the PC.



Method One

For Windows 7 and Vista full version installation media, after the "Press any key ... " black screen do steps #1 & #2 then skip down to step #5 below to continue.

For a Windows system repair disk start at step #3 below.

1) At the Select Language screen click next.
click any image to enlarge

2) At the next screen click Repair your Computer.

3) For a Windows created repair CD, after the "Press any key ... " black screen there will be a Loading Files screen.

4) Then click Next for this System Recovery Options dialog box.

5) At this System Recovery Options dialog box, make sure there is a dot at "Use Recovery Tools" and be sure to make note of the Location drive letter as it probably will not be C: and the correct drive letter must be entered in the following steps; then click Next.

6) At this System Recovery Options dialog box click Command Prompt.

7) In the command window that opens type this command below and hit the <enter> key, be sure to use your drive letter, where mine is F: for this demonstration yours probably will not be the same.

[B]sfc /scannow /offbootdir=[COLOR=red]f[/COLOR]:\ /offwindir=[COLOR=red]f[/COLOR]:\windows[/B]

8) You will get a blinking curser while it checks and attempts to repair any issues it may find, it could take quite a bit of time to complete.

9) To close the command window after the scan type exit and hit the <enter> key.

Though my demonstration / test found no errors to repair, yours may and if it does it may take you running this command a couple separate times to completely repair any issues it finds so don't give up after just one attempt.

For further important information on this process, see Option Two of this tutorial at the link below.

SFC /SCANNOW Command - System File Checker

10) To restart the PC when the command window closes, remove the Windows / repair disk from the ODD and click Restart in the System Recovery Options dialog box that's still open.

Method Two

It has been suggested by Brink to include this method for those dual/multi booting and for those that have issues with WinRE 'seeing' the Windows Operating System partition needing repair.

In the BIOS set the boot order to boot first from the CD/DVD Drive, insert the Windows full version installation DVD or a created repair CD and restart the PC so diskpart can be started, if need be, view this tutorial for those methods.

How to Boot to DISKPART at PC Startup

1) In the diskpart command window type list volume and hit the <enter> key.

2) After it lists the volumes type exit a single time and <enter>.

ckick to enlarge

3) Now type the command below using your specific volume drive letters <enter>.

If you are dual/multi booting or have a System Reserved partition as I do and the system boot files are stored on a separate partition than the Operating System partition needing repair, in any case, the volume drive letter where the system boot files are stored goes in the first part.

offbootdir=c:

In the second part you would use the volume drive letter for the Windows OS partition you want to attempt the repair on.

offwindir=f:

[B]sfc /scannow /offbootdir=[COLOR=red]c[/COLOR]:\ /offwindir=[COLOR=red]f[/COLOR]:\windows[/B]

4) You will get a blinking curser while it checks and attempts to repair any issues it may find, it could take quite a bit of time to complete.

5) Though my demonstration / test found no errors to repair, yours may and if it does it may take you running this command a couple separate times to completely repair any issues it finds so don't give up after just one attempt.

For further important information on this process, see Option Two of this tutorial at the link below.

SFC /SCANNOW Command - System File Checker

6) To close the command window after the scan type exit and hit the <enter> key.
Then remove the Windows disk from the ODD and restart the PC to start Windows.


Enjoy

Related Tutorials

---

• http://www.sevenforums.com/tutorials/69585-safe-mode.html?ltr=S
• http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html?ltr=S
• http://www.sevenforums.com/tutorials/3413-repair-install.html?ltr=R
• http://www.sevenforums.com/tutorials/681-startup-repair.html?ltr=S
• http://www.sevenforums.com/tutorials/700-system-restore.html?ltr=S
• http://www.sevenforums.com/tutorials/93347-copy-paste-windows-recovery-console.html
• http://www.sevenforums.com/tutorials/433-disk-check.html
• http://www.sevenforums.com/tutorials/139576-startup-repair-infinite-loop-recovery.html
• http://www.sevenforums.com/tutorials/105541-startup-repair-run-3-separate-times.html?ltr=S
• http://www.sevenforums.com/tutorials/238737-user-account-reset-password-windows-7-a.html

 

[looked]

Do a :

cd\windows\system32

Then run sfc /scannow

Thank you very much, the "cd" command means change directory so the command you suggested "cd\windows\system32" means go to the Windows directory where are all file systems, for anyone interested.
I didn't use ms-dos for many many years so I couldn't remember it!

Edit: the command works 100% but I got: "There is a system repair pending which requires reboot to complete".
Do you have a quick advice for this?

 

[Brink]

Hello looked,

Restart the computer to allow the pending system repair to finish, and see if you may be able to after.

 

[looked]

Hello looked,

Restart the computer to allow the pending system repair to finish, and see if you may be able to after.

Thanks Brink, restarted many times and anytime I get updating something then forget about and reverting to previous settings, this S@it happened since I decided to upgrade from IE8 to IE9 so I wanted to try my luck with the sfc command.
There are too many threads on Microsoft community regarding this issue I call them time wasting trash on internet because the forums are managed by Microsoft KIDS who pretend to give solutions by scripts, usually threads are endless and have no real solution.
Obviously they got no real life experience so anyone can be computer technician there even my little 3 year old nephew, just copy and paste the script!

 

[Brink]

Do you have all of your Windows Updates installed to make sure that there's nothing left to be automatically downloading and installing?

 

[looked]

Do you have all of your Windows Updates installed to make sure that there's nothing left to be automatically downloading and installing?

When I installed IE9 full offline package it seemed like it wanted to still update or download something from internet (maybe an update necessary to it) but on the computer there is no internet (just in case) so IE9 fails installation and anytime I restart the computer it attempts to update the system then it gives up and reverts back I believe to IE8.

This is an upsetting move from M$ because I chose a full offline package upgrade but it seems like I still need a working internet.

No, unfortunately this computer doesn't have internet access, M$ believe that 100% of its users have internet!

I might have to resort to illegal forums or warez/torrents to find the way to get offline updates, after all that is what M$ force me to.

 

[Brink]

I agree that's what is happening since you are offline.

I would recommend to avoid anything illegal since they often come packaged with malware or viruses. It's just not worth the risk.

 

[looked]

This might be off topic but I'll try System Update Readiness Tool for Windows, found the link here on Sevenforums then hopefully I can run sfc command.

 

[Brink]

Yep, that's one of the options in the blue note box that may be able to allow SFC to work afterwards.

 

[chris2505]

has anyone an idea of how one can force sfc to write the CBS.Log file to a specific place?

my Problem is, that there is no CBS.Log file after scanning with sfc like described in method 1.
After booting I have drive X: and my Windows is in drive D: and the CBS.Log file isn't anywhere.

 

[Brink]

Hello Chris, and welcome to Seven Forums.

Are you able to run SFC while in Windows instead?

http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html

 

[chris2505]

Hello Brink, no I don't because Windows doesn't start anymore.

 

[Brink]

In that case, see if you may be able to boot into Safe Mode to run SFC instead.

If not, then you might see if doing a startup repair may be able to help with the startup issue if you haven't already tried.

 

[chris2505]

I have been trying the Startup repair about 40 times now and the there is no way to get this pc back to live again. I think it is time to get the last backup but my Problem is about one year old and it a pc from a law firm. They don't like to make backups but they probably will complain if all their data is lost now. :-(

 

[Brink]

If you like, you could create a live Peppermint DVD/USB to boot from and backup what you can from Windows first. This way you could hopefully be able to import the data back afterwards.

http://www.sevenforums.com/tutorial...ate-live-cd-dvd-usb-use-emergency-backup.html

 

[chris2505]

thx, I did already an Emergency backup. I am just about to install the last Image and then we'll see how I can handle the data.

 

[jchap1590]

has anyone an idea of how one can force sfc to write the CBS.Log file to a specific place?

my Problem is, that there is no CBS.Log file after scanning with sfc like described in method 1.
After booting I have drive X: and my Windows is in drive D: and the CBS.Log file isn't anywhere.

after you run the sfc scan, enter the following:

findstr /c:"[SR]" %windir%\Logs\CBS\CBS.log >"[directory]:\sfcdetails.txt"

where directory is the drive letter of the target destination. this will create a .txt output of everything sfc did

note that drive letters will differ from when in Windows and when in Windows PE (recovery environment). use diskpart (steps below) to find out the current drive letters and disregard the fact that they are different from what you are used to seeing.

open an elevated command prompt window and enter the following commands:

1. diskpart
2. enter
3. list volume
4. enter

 

[dbseven]

What to do if you have a Windows Image on a USB Stick and missing files on c:/?
Thanks, dbseven

 

[Brink]

What to do if you have a Windows Image on a USB Stick and missing files on c:/?
Thanks, dbseven

Hello Donald,

What files are missing?

If system files, did you already run a SFC /SCANNOW command?

http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html

 

[dbseven]

YES, I did. I am missing my DVD and some others.
See View attachment sfcdetails.txt

 

[Brink]

If you a restore point dated before this happened available, then you could do a system restore to quickly fix it.