After logging in, there's a black screen and my cursor, nothing else! in Ubuntu 12.10

Question

I've been using Ubuntu(12.10) for a long time, and recently, my Ubuntu went through yet another update.

The whole update prompt showed up, following by a password prompt, and finally the good ol' progress bar...

Everything went well, and later on, I shut down my computer.

The next day, I turned my PC on, went to the login screen. I went ahead, and logged in, but after that, all I could see was a black screen, and my cursor!

I checked the forums, and got various tips, none of which worked...

Now I'm stuck with an Ubuntu installation that's completely useless.

One more thing:

I even tried logging in through Guest, but same problem! :\

My Computer Specs:
Motherboard: Intel DG41WV
Processor: Intel Core 2 Quad Q6600 @ 2.40GHz
Graphics: Intel G41 Express Chipset
RAM: Dual Channel, DDR3 2*2GB (4096 MBytes)
HDD: Seagate 500GB SATA

---- DETAILED INFO ----

To be a little more precise about my problem, after I log in, I can see a black screen and my cursor. Plus, importantly, I was able to see a login screen, hence I'm sure Ubuntu is rendering properly, and also pretty sure that there's no problem with the drivers (Otherwise I shouldn't even get a login screen, right?).

Anywho, another (probably) important thing is that, after logging in, I can hit Ctrl+Alt+1 and get up a recovery console.

The only thing that doesn't load is my actual GUI desktop

Then, I ran unity from the recovery console, it went through a few commands, got stuck at OpenGL for a few seconds, then zoomed throught many more lines of code, and ended up with this:

ERROR 2012-01-03 20.51.23 unity.launcher.Icon TrashLauncherIcon.cpp:62 Could not create file monitor for trash url: Operation not supported

*** glibc detected *** compiz: malloc(): memory corruption: 0x09c861d6 ***

After that. back at Ctrl+Alt+F7: Desktop Background + Cursor

So back to the terminal again, I had to hit Ctrl+C to get back again.

now, I typed unity again, and this was the output:

WARNING: no DISPLAY variable set, setting it to :D
compiz (core) - Info: Loading plugin: core
compiz (core) - Info: Starting plugin: core
unity-panel-service: no process found

so now I did a sudo service lightdm restart :

X10: fatal IO error 4 (Interrupted system call) on X server ":0"
after 131 requests (130 known processed) with 0 events remaining.
lightdm stop/waiting
lightdm start/running, process 2852

Im back at the login screen, and I login again, now Im back to black screen (Yes, I lost the Desktop Background as well)

So, once again, I try unity (same response as last time):

WARNING: no DISPLAY variable set, setting it to :D
compiz (core) - Info: Loading plugin: core
compiz (core) - Info: Starting plugin: core
unity-panel-service: no process found

And still a black screen! :\

Answer 1

Just for completeness, this problem also occurs when you mistakenly installed the "nvidia-319-updates" package, but you do not have an nVidia graphics chip on your system. In my case this package was an indirect dependency from package "libopencv-dev".

So, when you're running on an ATI or Intel grpahics chip for example, and you installed openCV (package libopencv-dev), OpenGL gets broken and you'll get a black screen with mouse cursor after logging in. To resolve in this case, just remove nvidia's packages:

sudo apt-get remove nvidia-*

See this bug on launchpad for more details

Answer 2

I've successfully solved the problem. Well, what I did was this:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:unity-team/staging

sudo apt-get update
sudo apt-get install --reinstall ubuntu-desktop
sudo apt-get install unity

That, followed by a reboot, is the recipe for a fix! :D

Answer 3

Maybe you need to reset compiz and Unity config files.

You can try a soft reset (only Unity/Compiz files, but I didn't test this): http://www.webupd8.org/2012/10/how-to-reset-compiz-and-unity-in-ubuntu.html

There's a hard reset: https://askubuntu.com/a/244064/123806

But it will erase config of some apps. Try it as a test user, go to tty1 (Ctrl+Alt+F1):

sudo adduser test

Return to tty7 (Ctrl+Alt+F7) and try login. If works, we confirm it's just a problem in your config file. Else follow the link above. (after tests, "sudo deluser test" and "sudo rm -Rf /home/test" will erase).

If Ctrl+Alt+T doesn't work...

First login and get blank screen, then Ctrl+Alt+F1, backup and remove your config file:

cp .config/dconf/user .config/dconf/user.bkp
rm .config/compiz-1/compizconfig/config .config/dconf/user

We need to remove both files at same time.

Ctrl+Alt+F7 and the expected is Unity will open.

Answer 4

I had same issue, but i noticed that after running

sudo apt-get remove nvidia-*

command, which did not changed anything (even after reboot)
there were some old unnecessary packages, and after removing them with command

sudo apt-get autoremove

and rebooting all was correct, desktop is loading as expected.

Answer 5

I had the same problem, and a shorter fix worked for me:

unity --reset

Followed by:

sudo service lightdm restart

Trouble is, you lose settings such as icon sizes, etc. These can be easily reconfigured using MyUnity or UbuntuTweak (from the software center).

(However, the problem comes back every time I connect an extra display to my laptop before booting. But that's a different problem, I presume. Discussed here: Ubuntu 12.04 Unity: Black screen with cursor only, when external display is connected before booting laptop)

Answer 6

try

ctrl-alt-f2

login

type:

sudo update-grub
sudo reboot