Getting the feeling that the issue is caused by using adblockplus with FF 55...
-- 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/1710987 Title: Since the update to 55.0.1 firefox hangs frequently with 100% cpu usage Status in firefox package in Ubuntu: New Bug description: Just received the upgrade. Unfortunately, firefox is hardly usable now. Rather frequently, CPU usage jumps up to 100% of a core, with the FF UI completely frozen. In some occasione, the hang is temporary. In others it is permanent and the application must be terminated. I suggest reverting ubuntu to FF 54 until the FF 55 issues are resolved upstream. ProblemType: Bug DistroRelease: Ubuntu 17.04 Package: firefox 55.0.1+build2-0ubuntu0.17.04.2 ProcVersionSignature: Ubuntu 4.10.0-32.36-generic 4.10.17 Uname: Linux 4.10.0-32-generic x86_64 ApportVersion: 2.20.4-0ubuntu4.5 Architecture: amd64 BuildID: 20170814193419 CurrentDesktop: KDE Date: Wed Aug 16 00:07:52 2017 EcryptfsInUse: Yes InstallationDate: Installed on 2013-12-12 (1342 days ago) InstallationMedia: Kubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1) SourcePackage: firefox UpgradeStatus: Upgraded to zesty on 2017-05-04 (103 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/1710987/+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