error: unknown filesystem, grub rescue> at the time of boot after merging two partitions

Rajesh Rakshe · 11-09-2011, 11:25 AM

error: unknown filesystem
grub rescue>

on my desktop i am having linux installed after windows xp, in xp i just merged two partitions together using Power quest partition magic, after that i restarted d PC and gt above prblm, i can not boot frm any of the OS CD or can not go ahead as grub rescue error appears. Plz help me

akuthia · 11-09-2011, 12:10 PM

Wait, you merged your linux partition and your xp partition? That isn't going to work, because they use two different filesystems (what your error message references) You're probably going to have to reformat and re-partition and re install your oses

suicidaleggroll · 11-09-2011, 12:21 PM

How exactly did you merge the partitions? It could be done in a way that would work (probably), but you'd have to be very careful about things. You would have to delete the windows partition first, then expand the linux partition to fill the empty space, then expand the linux filesystem to fill the partition. If you just brute force merged the two partitions together, the filesystems on both are now either non-existent or corrupted, and all of your files on both partitions are most likely gone (possibly recoverable with some low level file recovery software), and you'll need to reinstall the OS (which one were you trying to keep after the merge?).

Rajesh Rakshe · 11-09-2011, 12:44 PM

hello,
you havnt gt my prblm correctly...
I have the XP and UBUNTU in same partitions that is C drive. And i have merged the other two partitions i.e. G drive and H drive. After the partition merging i restarted the PC n got the above prblm. Also i cannot boot from my UBUNTU live cd. Plz help me

suicidaleggroll · 11-09-2011, 12:46 PM

You can't have XP and Ubuntu on the same partition, they have to be separate. How many hard drives do you have and how were they partitioned and how are they partitioned now?

Rajesh Rakshe · 11-09-2011, 12:52 PM

at the time of installing the UBUNTU i allocated some space from C drive in which XP ws present. After ubuntu installation that part of C drive ws is reserved as UBUNTU filesystem which cannot b visible n accessible frm XP. And the two drives which i hv merged are not carrying any of the OS or anything.

Rajesh Rakshe · 11-09-2011, 12:57 PM

also i want both OS working.. I dnt want to delete any of them. Frm other threading similar to this i came 2 know that i hv 2 reload/repair the grub frm live ubuntu CD by updating the grub. Bt further i the PC is not BOOTING frm any OS cd.

colorpurple21859 · 11-09-2011, 01:10 PM

What most likley happened by merging two partitons was the nameing of the partitions changed and grub isn't pointing to the partition that the grub files or at. If you aren't able to boot from cd, go into bios and change boot order to boot from cdrom first.

Rajesh Rakshe · 11-09-2011, 01:21 PM

i hv done all the bios settings. Still i cannot boot frm ubuntu live cd. Is there any other way? Any command line that can be executed at
grub rescue> _
at dis line i could execute ls command. If anybdy knw wat commands needs b executed at
grub rescue> so that grub will b updated to new parition settings and everything will b clear??? Plz help...

analogrival · 11-09-2011, 01:33 PM

I think a helpful thing to post would be your partition setup before and after the merge

For example:

Code:

Before:
Drive 1: 20GB Linux, 512MB Swap, 100GB Windows
Drive 2: 160GB Windows, 160 Windows

After:
Drive 1: 20GB Linux, 512MB Swap, 100GB Windows
Drive 2: 320GB Windows

AwesomeMachine · 11-09-2011, 01:37 PM

Reinstalling grub from a debian install CD rescue system would probably fix the problem. I agree that your partition numbering is different now, but grub-install can handle most anything reasonable. If PM allowed you to merge partitions with different formats, they both might be ruined.

If your machine is a Dell, HP or Compaq, the restore disk that comes bundled with the machine will repair the problem. There's a small repair-utility partition on some PCs made by the manufacturers listed above. If it changed position or was ignored by the new grub setup, it will always hang on the grub rescue prompt, because it's a DOS partition using grub-for-DOS.

If you lose that partition, I think you lose the BIOS setup program also. So then you must restore from the restore CD that was bundled with the hardware.

I ran into this after I made the reply: http://www.supergrubdisk.org/software/

colorpurple21859 · 11-09-2011, 02:01 PM

you can try booting your system from the grub rescue prompt by using this tutorial.
https://help.ubuntu.com/community/Grub2

Rajesh Rakshe · 11-09-2011, 11:22 PM

on superdrubdisk.org there are many dounloads. Will it be ok if i will use super grub2 disk. As error says only grub rescue??? Plz help

colorpurple21859 · 11-10-2011, 07:32 AM

Yes you can use the super grub2 disk to boot into your system and fix it. You will most likely have to edit the /etc/fstab file to reflect changes in you partiton naming before being able to boot into your system with out errors. Once booted into you system then will have to rerun grub-install and update-grub