Hi ETJR,
Thank you for the posting in our forum community.
According to your description, we understand that you cannot open MS Teams application on Mac, so in this given situation, first we suggest you to that if there is any new version update available for your Mac operating system, kindly try to update new
version update for Mac operating system.
Further, we suggest you to delete the “com.microsoft.teams” file folder under
Application support folder. Kindly find the ~/Library/Application Support under spotlight search on Mac and delete the “com.microsoft.teams” file folder, After that kindly try to download and install Microsoft
Teams from this mentioned link: https://teams.microsoft.com/downloads
Hopefully above things can work for you.
Regards,
Darpan