Since installing macOS Sierra beta 2 (Public) I have been experiencing extremely slow start ups on my Mac and the I believe the issue stems from Fantastical 2 starting when I boot up. Once I force quit Fantastical 2 all seems to run fine (In safari this takes and additional 10 - 20 minutes for some reason). However when I try to boot up any of my other calendar apps (Desktop Informant, Apple's Calendar app, and even Outlook) everything comes to a grinding halt again. Calendar apps are just not working on macOS Sierra, at least for me. Have no idea why this is happening. Reported the incidents to the macOS Sierra team via feedback app, and also to the makers of Desktop Informant and Fantastical 2. Luckily the iOS versions are working fine, but I do rely on my calendars a lot.