How to fix MBR in Windows 7?

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. 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. 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. Click on Command Prompt

Windows 7 System Recovery Command Prompt

5. Enter the following command on one line:

bootrec.exe /fixmbr

Fix MBR (Operating system found/logged on)

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

2. 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. Enter the command

bootrec.exe /fixmbr

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Filed Under: Tutorials Tags: boot, bootmgr, how to, mbr by sOliver - Tuesday, January 19th, 2010

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14 Responses to How to fix MBR in Windows 7?

Carlos Fernández said:
August 11, 2010 at 1:55 am

You saved my life!!!! Thank you so much!!!!!! Greetings from Costa Rica =D
sOliver said:
August 11, 2010 at 3:51 am

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 ;)
rysquash said:
August 23, 2010 at 1:54 am

what do i do if my hard drive dosent show up in system recovery options?
sOliver said:
August 23, 2010 at 2:09 am

Please read the comments of this article:
http://windows7themes.net/missing-operating-system-windows-7.html

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.
Yaro Kasear said:
August 30, 2010 at 3:41 pm

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.
pera said:
October 24, 2010 at 1:31 am

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.
Vic said:
October 28, 2010 at 8:58 pm

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!!
Alan said:
June 28, 2011 at 5:12 pm

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!!!
Bwit said:
August 20, 2011 at 5:40 pm

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.
qpagurom said:
September 19, 2011 at 6:10 pm

@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 ^^
lionel said:
October 16, 2011 at 5:00 pm

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 ;)
Laura said:
October 25, 2011 at 6:43 pm

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?
Jerry said:
December 19, 2011 at 11:04 am

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!
jaime said:
January 14, 2012 at 6:40 am

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

“a device attached to system is not functioning”

is this fixable?