Troubleshooting Ubuntu Boot Problems

01 Dec 2009

A few weeks ago my computer (then Ubuntu 9.04 Jaunty) froze. I rebooted and received this error message:

Kernel Panic — not syncing: No init found.
Try passing init= option to kernel

I eventually determined that the cause was a bad RAID controller, but you might see this message due to some other disk problem. You might also see a message like:

Target filesystem doesn’t have /sbin/init.  No init found.
Try passing init= bootarg.

I was a little disappointed with the various message board posts out there for troubleshooting such boot problems so I thought I’d document what I did. Hopefully it will help someone.

First, boot from the Ubuntu Live CD (either to command line or X-windows with a terminal app) so you get a working system without using the hard disk. To check the filesystem and correct minor problems you want to run fsck. First, you have to find the disk and partition:

sudo fdisk -l

Usually it will be /dev/sda1 but look over the output of fdisk to be sure. To run fsck:

sudo fsck /dev/sda1

If you get a message about a bad superblock you may be in trouble, otherwise there’s a decent chance fsck will fix your drive so that you can boot normally again.