Freeze on boot, lightDM will not start

Question

Having recently installed ubuntu 11.10 on a new computer after approximately a week of use I experienced a freeze on start-up. I think some updates where installed on previous session but I can't remember for sure.

Rebooting the without splash screen I receive two errors

Stopping automatic crash report generation [fail] 

which seems to be unimportant according to a quick google.

Second error

Starting lightDM display manger [Fail]

Heading to the console dmesg gives me these two messages of interest next to each other.

vboxpci:10 MMu not found (Not registered)
init: lightdm main process terminated

google suggests to me that this is the kernel checking if my motherboard has iommu, which I guess is used in virtual machines, guessing from google results. (for reference its a Gigabyte H67 usb3 B3). Trying to start lightdm again from command line does not help, same results.

I'm stuck, why is lightDM requiring a virtual machine? Or maybe the two lines are not related and I am missinterpreting? What's going on? Any suggestions to help me to get my system to reboot.

dmesg gives me one more error right at the bottom

init: plymouth stop pre start process terminated with status 1

but I think this may be because I went in to grub and removed splash from the startup options so I could see any errors.

Thanks for any help / ideas.

T

Answer 1

Turns out the virtual box warnings were nothing of importance, probably just something that if m'board had would allow virtualisation to run better or something.

I next tried starting X manually and that turned out to be the problem. Could not find NVIDIA drivers. For some reason an ubdate had wiped my NVIDIA drivers and Ralink pciwifi card drivers. Reinstalling both sorted the problem. I installed both of these manually. Why they disappeared I do not know. Maye to do with the upgrades that I think came though the last time I booted up?