I installed ubuntu 12.04 LTS around a month ago, and it's a great experience. Except for one thing: Lightdm crashes at seemingly random times, on average 2 times on a normal working day. I have no idea why, and I don't see a pattern. I've obviously looked through askubuntu and other resources but can't seem to find a solution, or even a clue as to what might be wrong.
Details:
- When a crash occurs the screen freezes, but the mouse cursor still moves freely. I can move the mouse around, but I can't click on anything.
- I see no discernable pattern in user behaviour when a crash occurs. I often have VLC media player open, and almost always a browser. At first I thought it might be the browser, so I switched from Chromium to firefox. The problem remained. So it isn't seemingly related to any one program.
- I can press CTRL-ALT-F2 to bring up a commandline, then run sudo lightdm stop and sudo lightdm start. This kills lightdm and starts it again, but I lose everything I was working on at the time. (this is also why I presume it's lightdm that's the problem - it might not be though)
Here are some clues about the system I'm running.
Hardware
- Hardware is a lenovo T60 with 2GB ram.
- The battery is dead, so it only runs on mains
- I did a memory check of the RAM, and it's OK.
- The CD-drive doesn't work
- Dual screen setup with laptop monitor and an external 1920x1080 screen driven by the T60's external screen output
- 3G Internet. Crashes happen both when I have the 3G USB dongle connected directly to the computer, and when I connect via wi-fi.
- The T60 is in a dock.
- External standard USB mouse and keyboard
Other clues
- Installed programs (on top of base installed programs): VLC, libre office, mysql, nginx, php-fm, firefox, blender, arduino IDE, GNU emacs.
- I sometimes at random times see the laptop monitor (never the external monitor) blink for what looks like a frame or two.
- at startup I see "TMP drive not mounted, would you like to wait" which I do, and it keeps on booting (not exact wording but pretty close)
- There is no pattern as to when the screen freezes. No particular action seems to trigger it.
I'm fairly new to ubuntu and linux, so I'm quite clueless as to what this might be.
Any ideas, and pointers would be much appreciated!