HowTo Recreate Grub Install And The Master Boot Record (MBR) If Corrupted

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Revision as of 19:07, 25 October 2009 by Rwh (talk | contribs)
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  • Problem: When booting NST from a hard disk install and you see the message: "Disk Error" (or something similar) on the screen after POST.
  • Solution: Typically, this is associated with a corrupt grub and/or MBR install on the hard disk. Use this HowTo to help recreate the grub and MBR to resolve this issue.


This HowTo shows the steps one can used to recreate a corrupt grub boot loader and/or MBR on an NST system. Start by booting up "NST Live" or NST on a "USB Flash Drive" hard disk install. This example assumes the corrupt grub and/or MBR is on the disk associated with device name: "/dev/sda" were partition: "/dev/sda1" is used for grub and the MBR is on "/dev/sda" sector 0.

  • 1) Make sure that there are no mounts using the "/boot" mount point:
[root@probe ~]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/mapper/vg_probe-lv_root
                     235338552   4335136 228613664   2% /
/dev/sdb1               198337     22358    165739  12% /boot
tmpfs                  1419416         0   1419416   0% /dev/shm
[root@probe ~]#


  • 2) Unmount "/boot" if currently mounted:
[root@probe ~]# umount -v /boot
/dev/sdb1 umounted
[root@probe ~]#