I agree with Dave, but any reason why it would be triggered only by either Firefox or Thunderbird?
At the time both the nouveau drivers and proprietary drivers had this problem. Currently , I have now wiped the machine and installed fresh 15.04, and the problem has disappeared. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1432492 Title: Firefox and Thunderbird freezes entire system after a few seconds of use To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1432492/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs