Root mount error while upgrading from ubuntu 10.10 to 11.04

Question

I had an electricity cut while I was upgrading from Ubuntu 10.10 to 11.04, now when booting the system I get the following message:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Any ideas how to solve this?

Answer 1

this goes after grub? if yes - you can change yours grub settings for hd and init=/bin/sh and run something like fsck

Answer 2

I had this problem once, way back with... I think it was Ubuntu 7. The Disk UUID's changed, I can't remember why.

I mounted manually, edited /etc/fstab and replaced the UUID entries with actual partitions (eg: /dev/sda1, /dev/sda2 and so on) and rebooted.

Answer 3

At the grub boot menu if you type e to edit the grub configuration for the line you've selected you'll see a line something like this:

linux /boot/vmlinuz-3.0.0-12-generic root=UUID=ddbfffc1-731c-4931-9129-75c5f42f8ecb ro single nomodeset

The culprit is the root=UUID=ddbfffc1-731c-4931-9129-75c5f42f8ecb part which probably still has the old UUID or partition listed. If you know the specific partition you can either set it to something like root=/dev/sda1 (or whatever your partition number is) and then type ctrl-x to boot or you can substitute the correct UUID which you can find by booting with a rescue disk and running the blkid command.

If you're lucky and your root partition has been properly labeled then you could also try root=LABEL=/.