I have the following problem: I was trying to upgrade from Ubuntu 13.10 to Ubuntu 14.04 and in the middle (after the necessary packages were downloaded and beginning to be installed), I ran out of space so the whole process froze. After that the only thing I could do was to reboot.

But after the reboot I start getting a:

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

CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-24-generic #47-Ubuntu

:

:

and continues with some Call Trace...

I can still enter the grub menu and select between old kernels and in this case it actually boots correctly with Ubuntu 14.04 but then I cannot do anything through the Unity GUI. I can however use a virtual console with Ctrl+Alt+F1 for example...

Anyone had the same problem or knows any way to fix this?

Thanks!