Comment 1 for bug 455157

Does this occur with the absolute latest daily-live CD (http://cdimage.ubuntu.com)? If so, please boot with the upstart debug option. Select your language at the CD boot menu, then press F6 followed by escape to bring up the kernel command line. Enter --debug just before the -- mark, so the line looks something like "...quiet splash --debug --", then press enter to boot. Take a picture of, or record on paper, the messages that appear at the end of shutdown.

Thanks!