Comment 6 for bug 1464917

I see this intermittently mostly after an internet session and I see at least 2 questions with total 5 upvotes on askubuntu.com concerning this hang on reboot or shut-down on 15.04 specifically. Most are hard booting after the hang. I found doing Ctrl+Alt+F1 followed by Ctrl+Alt+Del will continue the reboot. I will attempt to follow @Martin Pitt instructions and gain some log data if it is helpful to you. Please let me know if this is something you would like me to do. I referred to this bug#1464917 to those on askubuntu.com Just trying to help. :)