What versions of Thunderbird?

Define "slow" please in terms of numbers.

Version, see screen shot.

Startup time 12,96 seconds.

As comparison Mac mail starts in 3,26 seconds and MS Outlook starts in 5,05 seconds on the same Mac.

In a virtual win 11 machine on the same Mac I get a startup time of 4 seconds with the same version of Thunderbird.

Does the same happen when you start Thunderbird in "troubleshoot mode"? Hold down the Alt (Option) key and launch Thunderbird ...

> In a virtual win 11 machine on the same Mac I get a startup time of 4 seconds with the same version of Thunderbird.

Tried disabling Thunderbird's access to the Mac address book?

"troubleshoot mode" did not do it, maybe one second faster.

"Disabling Thunderbird's access to the Mac address book?" I'm not sure where one does that but I removed it from the Thunderbird address book and "PANG" I got a startup time around 3 seconds 😊 One could say it solved the problem but it created a new one. It's not a showstopper for me but it would be nice to have continued access to the Mac address book.