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I have read every single post about system freezes, but cannot find my exact problem.

Basically, Ubuntu 11.10 is randomly freezing. When it happens, I cannot do anything, not even move the mouse. Everything is locked up, even the keyboard is not responding (num lock does nothing). I noticed that the CPU fan starts to spin faster when the system freezes, but I verified that the CPU temp is OK just a moment before the freeze, so it's not that.

My system was working OK one week ago, after using it for more than two months. Now, suddenly, I started getting this problem, it happens several times a day. Seems to me that it was just after installing some ubuntu updates, that included the 3.0.0-16-generic-pae kernel, flash plugin, and some other packages.

What I did to try to troubleshoot:

  • Looked in the different logs, none reflect anything at the time of the freeze.
  • Used the previous kernel version selecting it from Grub; the freezes still happen.
  • Uninstalled firefox as I initially thought it was related (it was acting weird). Still happening.
  • I ran the memTest86, it passes (executed only one pass).
  • Used Windows 7 for several hours just to see if there's any problem there. No freezes or crashes at all.
  • I tested during one entire session without opening any web browser, just to not use Flash or anything. Still freezing.

I say it's random because I don't seem to find any sequence of steps that lead to a freeze. It can be on battery or plugged, while doing something or while doing nothing. Got the freeze while watching a flash video. Got the freeze while using Eclipse or while using gedit (to look at the logs!). Anything basically, does not seem to matter.

How can I further troubleshoot? The logs don't seem to help, I guess nothing is getting logged.

This problem is really frustrating. While everything else (including drivers, programs, Unity) works flawlessly, this is making the system almost unusable, I know I can lose my work at any point.

Thanks for any help!

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closed as off topic by fossfreedom May 1 '12 at 12:31

Questions on Ask Ubuntu are expected to relate to Ubuntu within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.If this question can be reworded to fit the rules in the help center, please edit the question.

My problem is similar to that reported by infohata, sometimes the system seems to run fine and won't freeze for a few days even under heavy load.. Other times it will freeze even under light load... I opened a bug report there : – Louis Gagnon Apr 1 '12 at 18:14
This question should instead be filed as a bug report, thanks! Instructions here. – Jorge Castro Apr 26 '12 at 2:42

It sounds like you might be experiencing an X freeze. Details on how to troubleshoot these types of freezes are available at

See also: How do I report a bug?

share|improve this answer
Thanks, I just read through that. I don't have any way to do the 'SSH check', but I can tell you that the keyboard is locked up as well. Num Lock or Shift Lock do not turn the little light on, and that should always work. Also, another comment: if I do not reboot the computer when it's frozen, during all that time nothing it's going to get logged, not even from the kernel. An X freeze wouldn't stop the kernel (or others) to log stuff right? Seems to me that the hardware is totally halt. – montag Mar 13 '12 at 2:51

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