I am running Linux Mint 12 with Cinnamon and sometimes when I leave my computer idle for a while, it will lock the screen. Usually, when I move the mouse a login prompt will pop up, but sometimes it doesn't. Then it's just a black screen with the time and my full name on a bar at the top of the screen. I can move the mouse, but nothing happens when I click on anything. When this happens I am forced to hard shutdown my computer, which is obviously not good. Does anyone know how to solve this?

  • 1
    Not an answer, but something that will help with the hard shutdowns is installing and setting up acpid so that when you press your power button it will trigger a clean shutdown. Also, I've been experimenting with Cinnamon too, and I get this issue sometimes too so you're not alone. Commented Mar 5, 2012 at 6:50
  • Also, some systems usually have (or used to have) CTRL+ALT+DEL set to run shutdown -r now (that is, reboot). Also, see the "Magic SysRq" key, as suggested by @jasonwryan, which is a last resort before a hard shutdown/reboot (REISUB).
    – njsg
    Commented Mar 5, 2012 at 10:05
  • Does the screen lock display animated images of some kind? If you press Ctrl+Alt+F1 in that state, does it bring you to a text console? If you press Alt+SysRq+S, does it cause some brief disk activity? Commented Mar 5, 2012 at 22:49
  • Did you have VMware Workstation installed ? Sometimes it kills your Xorg key mapping.
    – daisy
    Commented Apr 4, 2012 at 7:20

2 Answers 2


Solving the issue would involve understanding why it is happening. You should start by looking through your logs to see if there are any obvious errors; begin with /var/log/Xorg.0.log and the lightdm log at /var/log/lightdm/lightdmlog.

To avoid having to do the hard shutdown, next time it happens, switch to a console with CtrlAltF1 (or any of the F_ keys between 1 and 6) and login and restart the display manager with:

sudo service lightdm restart

You can then switch back to the console that X (your GUI) is running in with CtrlAltF7 where you can log back into your Mint desktop.

  • Unfortunately, when this happened to me I couldn't switch VT's, so that might not be a solution. Commented Mar 5, 2012 at 6:54
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    In that event, it's time for the Magic SysRq key...
    – jasonwryan
    Commented Mar 5, 2012 at 7:24
  • Huh, that's interesting. Never knew about that one. Personally, I just configured acpid to perform as safe shutdown on pressing the power button, and then use that to perform a safe reboot if I have to. Has the added advantage of just pressing the button on the front of my box to shut it down at the end of the day. This is still very useful info though, thanks! Commented Mar 5, 2012 at 8:37
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    If you can't switch terminals, then it sounds like an X11 driver issue — do you have any other computer around you can network with that one to see logs and play with the computer after the "lockup" happens?
    – njsg
    Commented Mar 5, 2012 at 10:08

I'm having the same trouble. I haven't found a solution yet, but you can avoid losing your work pretty easily. Hit ctrl-alt-F1 to get a terminal, log in, and run a ps -A | grep cin

then kill all the cinnamon-screensaver processes.

Then run DISPLAY=:0 cinnamon --replace

Then switch back to your main screen with ctrl-alt-F7 and continue working.

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