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How to fix MBR in Windows 7?

Written by: Oliver Krautscheid - Published: Tuesday, January 19th, 2010

It can happen that your MBR will be corrupted/damaged after a cold-start of your PC and then you need to know how to fix the MBR in Windows 7. Usually, you will encounter the dreaded error message: “Operating System not found“. There’s a really easy command that can be executed via the command line utility to fix it. But how to access the command line tool without operating system in the first place?


Fix MBR – Operating system not found

1. Step Start PC, Insert Windows 7 DVD and hit a key when asked to. You may have to change your boot order to boot from DVD!

2. Step Click on “Repair your computer“:

Windows 7 Repair your computer

The installer will scan your PC for previous Windows installations:

Windows 7 System Recovery Options

Select Operating System

4. Step Click on Command Prompt

Windows 7 System Recovery Command Prompt

bootrec.exe /fixmbr

Fix MBR (Operating system found/logged on)

1. Step On boot up press F8 and select “Repair your computer”.

2. Step Next, Windows 7 will automatically search for errors. Let it check for errors and when it’s done close the window. At the bottom you will see the “Command Prompt” tool. Click on it.

3. Step Enter the command

bootrec.exe /fixmbr



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Written by: Oliver Krautscheid
Oliver is the founder and lead editor of this site. He is interested in finding new ways to break Windows, find common errors and help others to fix them. Aside from that, he loves to fully customize systems with Rainmeter and Dreamscene, find out more about ancient civilizations like the Chachapoya, sharpen his digital photography skills and create software with a small group of selected developers. If you would like to connect with him to discuss anything, send him a mail!

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14 Responses to How to fix MBR in Windows 7?

  1. Orange Community Approved Comment:
    Carlos Fernández said:

    You saved my life!!!! Thank you so much!!!!!! Greetings from Costa Rica =D

  2. Orange Community Approved Comment:
    sOliver said:

    You’re welcome. “Missing operating system” message can be scary, eh? Luckily, it’s easy to fix a broken master boot record. You can be happy that it wasn’t a broken hard drive ;)

  3. Orange Community Approved Comment:
    rysquash said:

    what do i do if my hard drive dosent show up in system recovery options?

  4. Orange Community Approved Comment:
    sOliver said:

    Please read the comments of this article:

    Have you tried loading the drivers for your hard drive as recommend by Windows 7? You might have to re-install Windows 7. Booting into DOS and running the commands might work.

  5. Orange Community Approved Comment:
    Yaro Kasear said:

    Install GRUB. I use Linux, I don’t want to use the crippled Windows bootloader for dualboot.

    My MBR will always belong to Linux, never to Windows.

  6. Orange Community Approved Comment:
    pera said:

    win boot loader is not crippled, it is user friendly. It is made to load windows os, and if you didn’t know, you always using win bootloader, since grub is just “first boot loader” even for linux. But that is for some other discussion.

  7. Orange Community Approved Comment:
    Vic said:

    Thanks a lot!!!! you save my Life!!! i tryed to install ubuntu on a USB, and got boot problem :/
    Fixed with your Great Tutorial.. Thanks!! Thanks!! Thanks!! Thanks!!

  8. Orange Community Approved Comment:
    Alan said:

    Many thanks for the advice. System now back to normal. Paragon Partition manager is not for the faint hearted and does not uninstall the boot manager correctly!!!

  9. Orange Community Approved Comment:
    Bwit said:

    Good article but what is 7-Zip 42? You don’t say and the way this is written I’d think it was part of the article had to do with MBR repair ??? Its a zip program so NOT a good presentation and confusing. If I don’t understand it I don’t download it and I am sure the majority wouldn’t.

  10. Orange Community Approved Comment:
    qpagurom said:

    @Yaro Kasear, okay, you use Linux, because that’s the best OS, but many users even did’t know what it is, so take them chanse to fix their mbr :)

    Thanks for this article, it was save not mine, but my friend’s ass ^^

  11. Orange Community Approved Comment:
    lionel said:

    You save my life too. The virus Boo/Tdss.D was in the mbr.
    I format my computer and he resist.
    With the action fixmbr, he is gone now.
    Thanks a lot. The command bootrec.exe /fixmbr save my life ;)

  12. Orange Community Approved Comment:
    Laura said:

    I’ve got something in the windows 7 MBR, but I don’t have a Windows 7 disk for the version of windows installed. The other disk I have won’t work any suggestions?

  13. Orange Community Approved Comment:
    Jerry said:

    After running the command “bootrec.exe /fixmbr” I get the message “A device attached to the system is not functioning”. How bad is that? Any ideas about it? Thanks in advance to everyone!

  14. Orange Community Approved Comment:
    jaime said:

    I am having same promlem as Jerry. I get an edit

    “a device attached to system is not functioning”

    is this fixable?

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