When I shutdown or reboot my Ubuntu 12.04 it doesn't ever finish shutting down.
I end up stuck on a black/blank screen and have to hold the power button to shut it down.
Does anyone know where I can begin debugging this issue?
Thanks in advance
You can find the logs at
Check the logs to get a better understanding of what is happening.
Also, try typing
I can't comment, so I'll post this as an answer:
I had the same issue on my 12.04 recently; in my case, it was due to one program (in my case pcscd) that wasn't stopped properly at shutdown and caused a 'cpu-lockup'. So, to turn of the splash screen (the ubuntu with the five dots):
What messages are displayed on the screen? (look for something like "some process PID locks ..." (I forgot what the exact terms are...). If necessary, you can take a picture and post it here.
If you can confirm a process not being stopped normally, we can proceed by stopping it at shutdown via runlevel commands
I solved this problem by logging out first, then shutting down from the login screen. Shutting down without logging out first was resulting in a black screen, but with the power on the computer still on. I have Ubuntu set up with only one user so I'm not sure what's causing this problem. I haven't had a look to see if there are any processes running that are preventing shutdown as I'm very new to Linux and I don't actually know how to do that. A bit of searching will probably reveal the solution but if anyone can enlighten me here that would be great.
By default, the latest ubuntu install (12.04.2, and few others behind) hides messages and shows a nice animated image (splash) in a fancy resolution.
To make sure to view the console and possibly see what's hanging behind that dark screen:
/etc/default/grub (edit & save):
Now update grub boot entries with these new defaults:
And at your next start/shutdown process, you should see message lines with
nomodeset: You usually can toggle between the splash screen and the console messages with