I just spent a number of hours in trying to make my 12.04 boot again, after it put itself in a strange hang in splash screen.
After many trials and errors involving false leads such as
- nvidia-common driver
- hanging after "Checking battery state"
- failure in mountall
- failure to mount the swap due to encrypted home directory
and dealing with grub plymouth and others, I traced the problem to being related to lightdm. I changed to gdm, and the problem was solved. Could I have saved this fiver hours waste of time by using a log file, or any other information that could help in finding the difficulty that lightDM was experiencing?