Thunderbird incredibly slow after latest update (91.4.1)

Hello everyone,
I have Thunderbird installed through the packet manager and I’m currently running version 91.4.1.
I noticed that after the latest update it has become incredibly unresponsive and slow. Sending mail usually results in a timeout error and receiving mail is delayed by multiple hours.
At first, I assumed a network error on my email providers side, but I have a Nextcloud instance running the email addon with similar network settings and it works just fine.

Has anyone noticed similar issues? Is there a workaround available? I have not found anything related so far.

In case you need further details on my installation ore there are logs I could check, please point me in the right direction.


Welcome to the Forum :wave:

You wanted to write package manager, right?:wink:

Not sure, but have you tried just clearing the cached files?

rm -rf ~/.cache

Archlinux users also report that Thunderbird 91 feels sluggish / slow, high idle CPU usage

There’s also this bug report on

Thanks for the fast responses!
Of course I meant to say package manager :wink:

I’ve just tried deleting the cache folder, but sadly that didn’t help. But I noticed my CPU fan ramps up when trying to send a message and there are two Thunderbird processes with very high CPU usage.
I’m probably affected by the mentioned bug, but the workaround didn’t work for me, since the settings were already configured as suggested.

Then the best option would be to wait for the thunderbird devs’ to fix the issue and roll it out as an update, it seems …