HOWTO: Restore GRUB (if your MBR is messed up)

[rajaiskandarshah]

hi guys,

running windows xp and ubuntu on my acer travelmate 2301 notebook for the last 6 months. my prefered os is ubuntu where all of my main documents are.

since last week, i had a small project using visual basic, so i had to run winxp. yesterday morning, i installed a windows update in the morning when prompted, and in the evening winxp eventually(!) crashed. grub works ok and i can get to ubuntu no problem and even browse the files under winxp. but winxp will only get up to the splash screen, then there is the blue screen of death and the computer will restart.

will the following work ?? and any advice ?
1. copy my documents to another computer on the network
2. restart the computer with winxp cd and select the recovery option
3. run the fixmbr command
4. restart the computer as normal to winxp
5. restart the computer with ubuntu install cd and reinstall grub as per the top post
6. restart the computer to grub

any other potential issues ?

[adrian15]

If you do not want to mess up with commands...

Note: This method works very well with system with only one Linux... if you have more than one Linux Super Grub Disk will restore the first Grub that it will find on your partitions.

• Download Super Grub Disk
• Burn into a cdrom (better) or a floppy
• Boot from it
• Select: your language
• Select: Restore Grub on MBR
• Select: Auto
• You see the message: SGD has done it!
• Reboot
• You're done.

[jonathansizz]

Hi

I've looked through the posts but none of the methods described seems to be quite what I am looking for. I have Ubuntu 5.10 as my main distro. I installed this first. Later I installed 6.04 preview, and this installed its own GRUB. Now, I want to remove 6.04 altogether but when I tried this GRUB no longer booted my system (presumably as it was looking for the no-longer-existant GRUB from the deleted 6.04 partition). So I reinstalled 6.04 in order to be able to boot into 5.10. What I need is to be able to remove 6.04 but have GRUB boot 5.10 (from the 5.10 partition?). Here is the relevant info:

ubuntu@ubuntu:~$ sudo fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 14797 19457 37439482+ 83 Linux
/dev/sda2 1 14216 114189988+ 83 Linux
/dev/sda3 14217 14796 4658850 5 Extended
/dev/sda5 14217 14594 3036253+ 82 Linux swap / Solaris
/dev/sda6 14595 14796 1622533+ 82 Linux swap / Solaris

Partition table entries are not in disk order
ubuntu@ubuntu:~$

I think 6.04 is on sda1 and 5.10 is on sda2. So I think I need to have the asterisk next to sda2? sda5 is the swap for 5.10 and sda6 is the swap for 6.04

What is the best way of fixing this?

Thanks for your help!

[jonathansizz]

Sorry! I posted in the wrong section

[Hawkeye501]

vnbuddy2002 im new to linux, my first install on a Compaq Proliant 3000 server, and I had that problem, GREAT NEWB document! helped me fix my prob

[Hawkeye501]

ugh i did do something wrong, grub failed to load

[phbc50]

Hello,
After installing another OS I lost the mbr on my HD (hda with ubuntu on hda7), here is the solution that I found to work :
- boot the ubuntu LIVE CD
- go in console, and change user to root with su root
- make a temp dir to mount the ubuntu partition :
mkdir /mnt/hda7
- mount the drive with :
mount -t ext2 /dev/hda7 /hda7
- chroot to the mounted system :
chroot /dev/hda7
- run grub at the promtp : grub
then :
grub> root (<tab>
where <tab> is an actual TAB which returns the hd that grub recognises, in my case hd0 hd1 hd2
then :
grub> root (hd0,5) # in my case the hda7 partition is recognized by grub as (hd0,5)
grub> setup (hd0,5)
grub> exit
then reboot and it worked...
HTH
regards,
phbc50

[charsiubao]

i've used the live cd method to fix the error 17...but i get the error every so often. i feel like that should definitely not be happening so often. any suggestions/comments as to what the problem may be?...

[jdpipe]

If you need to restore your original Windows MBR / boot sector (for example if you messed up during your Ubuntu installation), see this post.

[SVFUSiON]

i don't see /boot just ext and swap