Fix MBR

Category: Hard Drives

"I was trying to fix a spyware problem and it seems I messed up my computer. Now when I start Windows XP, I get the 'MBR Corrupt' and 'Error loading operating system' messages. What should I do?"

Got a Damaged Master Boot Record?

master boot record
Although those messages sound pretty scary, there's a good chance your hard drive is still intact. In most cases this problem can be fixed with a simple procedure that repairs your Master Boot Record (MBR). When you start your computer, the BIOS (basic input/output system) looks for the MBR on the first sector of your hard drive. The MBR tells the BIOS which partition on the hard drive contains the operating system.

So... if the MBR is damaged, the BIOS can't locate and start the operating system. When your BIOS detects a damaged MBR or boot sector, you'll see ominous messages like Invalid partition table, Error loading operating system, or Missing operating system. In some cases, dark clouds will apppear on the horizon, and you may hear the distant rumble of thunder. But fortunately, the Recovery Console offers some tools to help clear up the problem.

Repairing a Damaged MBR

Your Windows XP setup CDROM has a tool called the Recovery Console, which is designed to help you repair a damaged master boot record or boot sector. To start the Recovery Console and fix your damaged MBR, follow these steps:

  1. Restart your computer with the Windows XP Setup disk in the CDROM drive.
  2. If you are prompted to press a key to start the computer from CDROM, do so quickly. Otherwise it may try to boot from the hard drive.
  3. After a few minutes, you'll see a prompt to press the R key to start the Recovery Console.
  4. When Recovery Console starts, it will prompt you to enter a number corresponding to the Windows XP installation that you need to repair. In most cases, you'll enter "1" (which will be the only choice). If you press ENTER without typing a number, Recovery Console will quit and restart your computer.
  5. Enter your Administrator password. If you don't enter the correct password, you cannot continue.
  6. At the Recovery Console command prompt, type fixmbr and then verify that you want to proceed.

Your damaged MBR will be replaced with a shiny new one, and you should then be able to boot your system normally. In some cases, you may need to repair the boot sector in addition to the MBR. If your system still doesn't boot properly, repeat the steps above, but issue the fixboot command instead.

NOTE: These procedures assume that you have only one operating system installed. If you are an advanced user and have a multi-boot system with more than one operating system, you may need to do some additional reading about the fixmbr and fixboot commands at the Microsoft website.

Do you have experience with a damaged master boot record? Post your comments below...


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Posted by Bob Rankin on June 7, 2006 08:59 PM


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Related Keywords: Hard Drives   mbr   master boot record   boot sector   fixmbr  

Most recent comments on "Fix MBR"

(See all 38 comments for this article.)

Posted by:
Vail Teal
24 Jan 2008

I recently cloned my 60 gig HD to a 160 gig HD, using a compaq computer. The new hard drive works, but when I put the old HD in a non- Compaq computer, it will not load. (It still loads fine on the Compaq).
I tried using the fixmbr command, it said the mbr was a non regular one; I told it to repair anyway. Nothing happened.
I then used the fixboot command, but to no avail. Is there anything else I can do to get this drive to load?
I don't want to have to start from scratch, as there are a lot of programs on the HD, and I'm trying to avoid a 12+ hour re-install.

EDITOR'S NOTE: I wonder what Compaq could have done to make the drive unusable in other machines... Try the TESTDISK program...


Posted by:
Lima
06 Feb 2008

I receive the message 'error loading operating system'. My PC does not boot from safe mode and I cannot boot from CD because CMOS settings does not allow me to change the boot priority to CD from IDE.

EDITOR'S NOTE: That's very odd... how would you first load the OS onto the hard drive if you can't ever boot from CD?


Posted by:
steven
26 Feb 2008

Usually if you have destroyed your MBR, (or, like me have removed the partition where grub resides (for dual boot, yes)) there is an easy fix. Sift through your old floppies, and get a DOS floppy from it. Boot it, and type "fdisk /mbr". Job done.

No need for XP boot cd's (some pc's just come with a re-install disk, no possibility to boot into repair console from M$) or Administrator passwords. Just a good old floppy.

PS: I have to take back my words to my friend Jan; I now agree floppy drives can be good for something after all :)


Posted by:
jashmin
05 Mar 2008

i have a problem -- i have dual boot in my system. in c drive i have vista and in d drive i have xp installed.and my problem is that my system only boots vista not xp and i want my boot operatig system to boot by choosing. i have tried everything to fix it.but no progress.
sometime it says ntldr file missing or sometime it says problem in mbr so i dont know what to do so can you help me out.
i dont want to format all drive and again install so please help me out from this problem

EDITOR'S NOTE: Sounds like the FIXBOOT command might help you.


Posted by:
bill jones
19 Apr 2008

I am receiving messenger service pop ups from system to alert.stating(Stop! immediate attention required) windows has found critical systems errors in my registry. and one from another registry cleaner... I have used windows recovery to fix my mbr several times and I still receive this message pop up, I have even re installed my windows xp several times... how can I resolve this issue? please help me I cannot even play a pc game without interference.

EDITOR'S NOTE: Here's a page with instructions on how to turn off the Windows Messenger Service: http://www.itc.virginia.edu/desktop/docs/messagepopup/


Posted by:
Umar Mohammed
17 May 2008

I have a compaq laptop and needed to format it. It came with a recovey partion. After running the recovery program i got a an 'mbr error' when booting. When using a xp cd it says that it doesn't detect a hard drive. Any suggestions about what to do? Btw, before running the recovery program there was no 'mbr error'.

EDITOR'S NOTE: That means your Master Boot Record on the hard drive got whacked. You can use the Recovery Console (http://askbobrankin.com/recovery_console.html) or look on this site for the TESTDISK program link.


Posted by:
NetSoul
23 May 2008

I have a problem with my harddrive.Last day, I found a bad sectors in my c: partition and I've changed my first boot sector on my harddisk using XP boot CD and then restarted my computer.At that time, my harddisk was known in CMOS detection setting. It clearly show my HD informations such as cylinders,heads,sectors,etc..). Then, memory detection is ok. But, HD detection has error. HDD error.. Press F1 to resume.
So,How can I detect my HD? It only show in CMOS. But actually can't detect. Please help me!

EDITOR'S NOTE: If your BIOS cannot detect the drive, there is a serious problem with the disk. You may need a data recovery service. See http://askbobrankin.com/hard_drive_recovery.html


Posted by:
shaveen
08 Jun 2008

I have a really serious problem which i havnt been able to solve in over 6 months. I have an Acer Travelmate 3290 Core 2 Duo notebook. The problem is, when I bootup, the normal bootup screen stays up for about 10 mins and then the screen displays "Operating System not found". I tried changing the order in Boot Setup, but the Hard Disk is not detected. I know the HD works becouse i connected as an external hard and it's detected without a problem. The funny part is, when the HD is not in the laptop socket, the bootup screen barely stays up for 2 seconds. Hope someone can assist me.... Thanks....

EDITOR'S NOTE: DId you try any of the suggested fixes to repair the master boot record?


Posted by:
George
19 Jun 2008

I had a dual boot Windows XP and Red Hat Enterprise Linux Workstation 4 Update 4 system. I needed to remove the RHEL so it could be reinstalled fresh for some documentation and testing. So with the mindset of "no guts, no glory" I did the steps above i.e. fixmbr and then for the heck of it also did a fixboot. The system rebooted fine into Windows XP. There were no GRUB complaints, problems, or any issues. I can only vouch for RHEL WS 4 U 4 and not other Linux flavor.


Posted by:
LJ
02 Jul 2008

Im getting a GBUB 21 error and I cant even get to the recovery console! When booting from XP CD, it gets to where its supposed to ask you if you want to install or repair but I get a BSOD and a stop error with an error in dmboot.sys
Anything I can do?

EDITOR'S NOTE: Yes, the problem could be a damaged Setup CD, a defective CDROM drive (or cable), or flaky RAM memory. I would swap them out in that order to resolve.


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