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 Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/1432492 Title: Firefox and Thunderbird freezes entire system after a few seconds of use Status in The Mozilla Firefox Browser: Unknown Status in firefox package in Ubuntu: Incomplete Bug description: Description: Ubuntu Vivid Vervet (development branch) Release: 15.04 firefox: Installed: 36.0.1+build2-0ubuntu1 Candidate: 36.0.1+build2-0ubuntu1 Version table: *** 36.0.1+build2-0ubuntu1 0 500 http://mirrors.accretive-networks.net/ubuntu/ vivid/main amd64 Packages 100 /var/lib/dpkg/status The whole system freezes after opening firefox. Hard reset required. Related bug: https://bugs.launchpad.net/ubuntu/+source/thunderbird/+bug/1432488 ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: firefox 36.0.1+build2-0ubuntu1 ProcVersionSignature: Ubuntu 3.19.0-9.9-generic 3.19.1 Uname: Linux 3.19.0-9-generic x86_64 AddonCompatCheckDisabled: False ApportVersion: 2.16.2-0ubuntu3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC1: black 1959 F.... pulseaudio /dev/snd/controlC0: black 1959 F.... pulseaudio BuildID: 20150306140302 Channel: Unavailable CurrentDesktop: Unity Date: Sun Mar 15 22:01:45 2015 EcryptfsInUse: Yes Extensions: extensions.sqlite corrupt or missing ForcedLayersAccel: False IfupdownConfig: # interfaces(5) file used by ifup(8) and ifdown(8) auto lo iface lo inet loopback IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite) InstallationDate: Installed on 2014-04-21 (329 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417) IpRoute: default via 192.168.1.1 dev eth0 proto static metric 1024 169.254.0.0/16 dev eth0 scope link metric 1000 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.100 IwConfig: eth0 no wireless extensions. eth1 no wireless extensions. lo no wireless extensions. Locales: extensions.sqlite corrupt or missing MostRecentCrashID: bp-d89e64a8-90ce-4922-add5-6cfba2140512 PrefSources: prefs.js [Profile]/extensions/https-everywh...@eff.org/defaults/preferences/preferences.js [Profile]/extensions/{0AA9101C-D3C1-4129-A9B7-D778C6A17F82}/defaults/preferences/rikaichan.js Profiles: Profile0 (Default) - LastVersion=36.0.1/20150306140302 RelatedPackageVersions: google-talkplugin 5.38.5.0-1 rhythmbox-mozilla 3.1-1ubuntu2 RfKill: RunningIncompatibleAddons: False SourcePackage: firefox SubmittedCrashIDs: bp-d89e64a8-90ce-4922-add5-6cfba2140512 Themes: extensions.sqlite corrupt or missing UpgradeStatus: Upgraded to vivid on 2015-03-16 (0 days ago) dmi.bios.date: 05/19/2009 dmi.bios.vendor: American Megatrends Inc. dmi.bios.version: 1605 dmi.board.asset.tag: To Be Filled By O.E.M. dmi.board.name: P6T DELUXE dmi.board.vendor: ASUSTeK Computer INC. dmi.board.version: Rev 1.xx dmi.chassis.asset.tag: Asset-1234567890 dmi.chassis.type: 3 dmi.chassis.vendor: Chassis Manufacture dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr1605:bd05/19/2009:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnP6TDELUXE:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion: dmi.product.name: System Product Name dmi.product.version: System Version dmi.sys.vendor: System manufacturer no_proxy: localhost,127.0.0.0/8,::1 To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1432492/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp