From another side I got the hint, that miss-configured (web)rendering could be the source of the problem and cause lots of time spent in error logging. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1772673#c11
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to thunderbird in Ubuntu. https://bugs.launchpad.net/bugs/1959747 Title: [upstream] Very high CPU and slow responsiveness in Thunderbird 91 Status in Mozilla Thunderbird: Confirmed Status in thunderbird package in Ubuntu: Triaged Bug description: Very high CPU and slow responsiveness in Thunderbird 91.5.0. Just moving the mouse cursor over a message list results in 365% CPU for me. I had to set this in the config editor to fix it: gfx.webrender.force-disabled = TRUE Upstream bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1730423 To manage notifications about this bug go to: https://bugs.launchpad.net/thunderbird/+bug/1959747/+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