Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm in the process of upgrading to 12.04 (via command line, from 11.10).

Everything was downloaded and it was happily unpacking and replacing packages when my system froze.

I can move my mouse, but clicking on anything gets no response, and the display is not changing other than the mouse moving.

What can I do? I'm guessing simply holding down the power button until it turns off is a bad idea, but I don't know what else to do that would get things moving again.

(I couldn't find this question, but if it has already been asked and answered then a link would be helpful.)


share|improve this question
up vote 1 down vote accepted

This looks like a software failure, and you can try to power it down with the power button(hard reboot). If you are concerned about general FS, corruption, you can try the REISUB trick. Just hold down [ALT]+[SYSRQ]+[[KEY]], replacing [[KEY]] with R, then E, then I, then S, then U, then B, waiting a few seconds between each. If at the end it does not hard reset, use the power button. If you have issues after the reboot, try using dpkg -a or apt-get to remove any offending packages.

share|improve this answer
Thanks! And excuse my ignorance, but what is [SYSRQ]? – Adina G Apr 30 '12 at 20:24
@AdinaG It's the [Print Screen] key, near the upper-middle-right corner of the keyboard, above [Insert]. Some rare keyboards have a separate key, in which case you should use just the key without alt, and then if nothing happens after pressing all six combos then you should try it with [Alt]. BTW nothing may happen for some of the keys. Keep pressing [Alt] and [SysRQ]. – hexafraction Apr 30 '12 at 20:27
Ah, thanks! Now the reboot is stuck on the line "*Stopping System V runlevel compatibilit[ OK ]". – Adina G Apr 30 '12 at 20:41
@AdinaG I would go into your BIOS settings and try to disable any sort of 'virtualization' technology or option, especially if you have an AMD CPU. That often helps me with System V issues. Then, try a reboot. You may experience about a 10-20% drop in performance, especially multitasking. – hexafraction Apr 30 '12 at 20:46

Update: I rebooted using the trick Robert mentioned. The system kept freezing while booting, so I rebooted again and immediately held down the left shift key to get kernel options, and chose recovery mode. From recovery mode I ran dpkg which finished the installation; I can now boot normally and it seems to work.

share|improve this answer
This should be a comment, but it's great that you fixed your problem! Thanks for giving me this problem so I can learn from it. – hexafraction Apr 30 '12 at 21:39
@ObsessiveSSOℲ Most of this is a separate answer; only a tiny bit overlaps with your answer. – Eliah Kagan Jan 8 '13 at 18:57
@EliahKagan Exactly; more knowledge and alternatives to add to my memory. – hexafraction Jan 8 '13 at 20:08

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.