Lightdm getting killed during boot process

[MR ZenWiz]

This morning when I went in to work, all the machines were off (we had
a power outage over the weekend) and I had shut mine down on Friday.

However, when I booted the machine, lightdm was killed during the boot
and it took me a reboot and some log scoping to figure out what
happened.  When I started lightdm from the console, everything went
fine.

I had to reboot again due to an update, and the same thing happened.

What would kill lightdm during startup but allow it to run thereafter?

Thanks.

MR