Can you be more precise about "after some time runnning"? Is this a couple hours, a day, several days?

Junk and Trash folders are empty?

Is filter logging disabled at Tools > Filters?

What happens after Help | restart with addons disabled?

Sorry for the delay, I tried to diagnosed the different possibilities. Some time = a couple of hours. Junk/trash does not affect the problem. Filter does not affect the problem.

I am running the followings addons: Lightning (who doesn't) Messaging Menu and Unity Launcher integration Provider for Google Calendar 4.4.2 Send later (no effect)

It is possible that the Google calendar addons has some influence, not the others. I also noticed that I have a lot of "server timeout" in the activity manager. When Thunderbird is trying to connect to the faulty server, the CPU activity runs high.

Hope this helps.

You didn't actually answer the question of whether Is filter logging disabled. :)

You should try for several hours with calendar disabled.

If there is still a problem, then try the performance profiler: 1. install profiler add-on into thunderbird from https://github.com/firefox-devtools/Gecko-Profiler-Addon/blob/master/gecko_profiler.xpi?raw=true

2. The follow instructions at https://profiler.firefox.com/ (videos BASED ON FIREFOX at https://profiler.firefox.com/docs/#/./videos-intro )

You must be using 67.0b3 or current nightly build.

I finally found what is causing the large CPU usage. In the activity manager, there is an "indexing messages" bar running forever: Determining which message to index in inbox.

Please let me know if there is a way to fix this.

Thanks, Pierre

Thanks for finding that this is related to indexing messages.

Can you run the profiler?

Will do, but I am traveling this week. Definitely later though.

pablanche,

What were your results ?

Please post in a new topic - this one is archived.