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Ubuntu on my laptop has frozen multiple times in last 6-7 months. Its not frequent but I can not relate the freezing to anything which I was doing.

Today it froze again when I was taking notes in class - approximately at 12:00 PM. During the freeze both mouse and keyboard stopped working. I tried Alt-Ctrl-F1, Alt-Ctrl-F2 etc without any success. After that I waited few minutes & then I restarted the laptop.

I checked /var/log/syslog and /var/log/kern.log and it seems that it did not log anything (I was not able to understand most of it). Please let me know if you can find something unusual at around 12:00 PM.

Is there any other log which might be useful?

Here are the /var/log/syslog and /var/log/kern.log files.

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closed as off topic by Marco Ceppi Nov 27 '12 at 14:57

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.

possible duplicate of What should I do when Ubuntu freezes? – Jorge Castro Jul 4 '12 at 15:54

Eventhough Linux is a very stable OS their are still numerous things that go on in the system that can cause erratic behavior, mostly when you are in your windows manager like Unity and Gnome etc. The good thing about linux is the ability to start and stop services that are hanging or causing you problems. If your window manager hangs instead of restarting your entire machine try the following key combination to restart your session.

alt + print screen + k  or ctrl + alt + backspace

This will exit your current session and return you to your login screen


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Ctrl-alt-Backspace is not enabled by default on Ubuntu since about 10.04 LTS ... Alt-Prt Sc-k works just dandy however. – fabricator4 Sep 30 '12 at 10:12

Although those key combinations work when the keyboard is working, Ubuntu (according to the forums since 10.04) randomly freezes including the keyboard and mouse. Keystrokes and mouse-clicks are not options. The only thing to do is reboot with the power button.

As for the question; I don't think it is isolated to your machine since people have been having the same problem consistently with various computers (old and new), graphics cards (Intel, Nvidia), and processors (Intel, AMD). The Ubuntu community has yet to be able to truly offer an answer to this problem. I'm sorry I couldn't give a more satisfactory answer.

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I'm not sure this is good advice. I'm yet to have a freeze that did not respond to Alt-SysReq keys, even if ctrl-alt-F1 etc was unresponsive. The power button should the absolute last resort - there's plenty of other things to try first. – fabricator4 Sep 30 '12 at 10:04

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