A few of us at work have had huge issues with Microsoft Teams on our Macs with not being able to login for seemingly no reason at all. After a lot of messing around with uninstalling, reinstalling, restarting my machine etc. I finally dug in and got my hands dirty.

Here’s how to fix it:

Either open a terminal and enter:

rm -rf /Users/*/Library/Application\ Support/Microsoft/Teams

OR manually navigate to…

/Users/<your-username>/Library/Application Support

…and delete the ‘Teams’ folder.

After that, reopen Teams, follow the steps, and you should be able to login okay.

Note: I also deleted the…

/Users/<my-username>/Library/Saved\ Application\ State/com.microsoft.teams.savedState

…folder but I’m 99.9999% sure that wasn’t necessary.

I hope that helps!