Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

I have installed ubuntu 12.10 after installation every things worked fined and for 2 weeks I've had no problem . yesterday I tried to log off and log in again but when I logged off it showed me a black screen and nothing happend I've waited for 30 minutes but still it was black . I had to press my laptop power button once to shut down my laptop.

I've had this problem on ubuntu 12.04 too. from yesterday every time that I want to log off this issue happens.

my laptop is hp probook 4520s .

share|improve this question
Can you press ctrl + alt + F1 to switch to a text terminal and workout the reason from there? You would probably see a list of tasks that were performed while your system was shutting down and one of them noted as [FAIL] instead of [OK] on the right side. –  Cyprian Guerra Jan 20 '13 at 16:50
Unfortunately these key won't work on that screen and I don't know what else to to –  Mohammad Jan 21 '13 at 8:41
something strange happend when I'm on battery my ubuntu will log off without any problem and I am able to start my lap top faster when it's off. but when it's plugged in to the adapter I'm not able to log off and that black screen appear. and when I want to start my ubuntu when it's off it takes longer . sometimes about 30 miniutes in a violet screen I should wait until it goes to my desktop –  Mohammad Jan 21 '13 at 8:48
Do you do the same thing on battery and adapter? Or do you e.g. close the lid when on battery (hibernation, I guess) and press the power button once when on adapter (would be a power off or suspend)? I understand you log out but how do you "shutdown" your machine afterwards? From what you've described so far, I'm guessing it stops right before cutting the power off which would mean the OS can't send the proper instruction via ACPI. Did you change anything in BIOS lately? –  Cyprian Guerra Jan 21 '13 at 13:06
I haven't changed anything in BIOS. sometimes I need to log out and log in again to my unity but when my laptop is connected to power source that black screen comes up. but this morning I was using my laptop on battery when I tried to log out it worked successfully and fast . –  Mohammad Jan 21 '13 at 13:26
show 2 more comments

2 Answers 2

I too am facing the similar issue with my hp pavilion g6 2314ax Laptop. I have installed Windows 7 along with Ubuntu 12.10 (3.5 Kernel) with Gnome desktop installed in it. The Laptop neither shuts down nor logs off.

I have tried sudo shutdown -h now There is no solution whatsoever in net. PLz Help!!!!

share|improve this answer
I found the 64 bit Ubuntu have had lots of problem with my laptop like froze in violet screen at boot loader for maybe 2 hour , unable to log off , unable to restart easily and etc , my solution was to install i386 version of Ubuntu on my hp probook 4520s and there are no more issues . if you have the same problems with 64 architecture you should do the same and you should know that you can install 64 bit windows alongside both Ubuntu versions . I've tried it and it worked. –  Mohammad Aug 13 '13 at 11:49
add comment

I don't know if it is possible but you could try going into terminal and issuing the shutdown command from there:

sudo shutdown -h now
share|improve this answer
I use this command for shutdown not log off . for log off this command is useful : sudo pkill -kill -u username but for the record this log off command has the same result black frozen screen . –  Mohammad Jan 21 '13 at 8:42
add comment

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.