The System File Checker (sfc.exe) is an useful tool that lets you scan the integrity of Windows system files, and repair corrupt or missing system files. Numerous cases have been resolved thus far by running Sfc.exe with the "scannow" parameter. However, there are situations where in a corrupt or missing system file prevents Windows from booting normally, and running Sfc.exe from Windows isn’t possible. In such cases, Sfc.exe can be run offline using two additional parameters, via the Windows Recovery Environment (Windows RE) in Windows 7 and Windows Vista.

Booting into Windows RE

Configure the boot order in the BIOS such that the first boot device is your CD/DVD drive.

Insert the Windows 7/Vista Setup DVD and restart the computer.

Alternately, you may use the Windows 7/Vista System Repair Disc if you have one.

When prompted, press a key to boot from the DVD. In the "Install Windows" screen, click Repair your computer

Select your Windows installation, and click Next

Editor’s Note: Make a note of the drive-letter of your Windows 7 installation, as seen from Windows RE. This is the drive-letter you want to reference when running Sfc.exe offline.

Click Command Prompt

To scan the integrity (and repair) a specific file, use this command:

sfc /scanfile=d:\windows\system32\zipfldr.dll /offbootdir=d:\ /offwindir=d:\windows

The above command scans the file zipfldr.dll and replaces it if required.

To scan the integrity of all system files and repair them, run this command:

sfc /scannow /offbootdir=d:\  /offwindir=d:\windows

This process takes some time (<5 min in my case) to complete, and there weren’t any integrity violations.


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16 Comments

  1. evegalla
    said this on Friday, January 3rd 2014 8:14 pm

    i have done the above instructions but it says Windows resource Protection could not start the repair service

  2. Me
    said this on Friday, June 28th 2013 1:19 pm

    What should I do if booth my boot directory and windows directory are on my c: partition?
    I tried: “sfc /scannow /offbootdir=c:\ /offwindir=c:\windows” , but nothing happens.

  3. Rich
    said this on Monday, April 22nd 2013 7:46 am

    Sudhir, and those having similar problems… my advice is to do just that… restart and try again. Chances are you exited out of one of long, boring, and often useless “starup repair”s, and it’s waiting on you to finish it before starting anything else. If it lets you go through one of those and (most likely being the case) if it comes up with nothing, it should let you choose “advanced recovery options” as a text link in the bottom. It is at this point that you should be able to select “Command Prompt” from the bottom as seen in the picture above.

    If in the case I’m not at all correct (just working from memory, here), then I guess google is your friend… unless you’re against CISPA, then perhaps duckduckgo is your friend.

  4. carol
    said this on Monday, April 22nd 2013 1:12 am

    if you have one for the disc but what if you dont

  5. Sudhir Naik
    said this on Wednesday, October 24th 2012 8:09 pm

    When I enter “sfc \scannow” or any other command, it says: “There is a system repair pending which requires reboot to complete. Restart Windows and run sfc again.”
    Please help.
    Thanks in advance
    Sudhir Naik

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