Today when I launched Mail app on Windows, it force-installed Outlook and closed itself.
Outlook won't show my Google Calendar without me letting them sync my Google stuff to Microsoft Cloud.
Shitheads.
P.S. some search tells me this is rolling out in tiers, as some people got this before
P.P.S. Uninstalling Outlook and opening Mail several times got it working (the first 2 times it just closed itself)
https://www.thunderbird.net