Teams not working on MacOS Big Sur

I had same issue with Team hanging on loading screen.

I quit Teams.

I deleted this folder

~/Library/Application Support/Microsoft/Teams

Then started teams and signed on with a different account.

That failed with a message and then I tried to sign in with the original account and it worked.

Hi Nik,

Thank you very much! The first solution didn't work but the second one yes!

The most important thing is to log in with an account. If you only have a business account, create a personal one and log in with that one.

Afterwards, when you see the dashboard you can try and log in with your desired account.

(deleting the /Teams folder from Application Support / Microsoft / Teams in-between tries is also a must)

It seems like the initial login process is blocked somehow when you try to do it with no account added or before the app dashboard is shown. 

Pretty obvious bug if you are trying to use a business account (which most of us are...)

I can confirm that deleting the Application Support/Microsoft/Teams and com.microsoft.teams folders in combination with logging into a personal account and then switching to the work account works.

It was not necessary for me to delete the folders in between the switch, just upfront. (didnt test to not delete them)

I have a MacBookPro 2019 with BigSur and latest teams from the website (today, now downloaded).

I have Big Sur and M1 chip, Teams wouldn't install just kept loading. I tried all suggestions (I had no Teams folder in library) with no success.

I got it working by logging in the Teams web plateform and inviting myself to a meeting. The app worked after that.

Good luck!

I am having Error code 2:-1009 when entering login email into app. Doesn't matter if it is private or business account - error all the time. Application support deleted, the same with catches. Teams version latest from MS site.

Does anyone know how to fix this issue?

I had same issue with Team hanging on loading screen.

I quit Teams.

I deleted this folder

~/Library/Application Support/Microsoft/Teams

Then started teams and signed on with a different account.

That failed with a message and then I tried to sign in with the original account and it worked.

HERO!!! thi fixed my issue of the hanging log on screen! Comon Microsoft, are you serious...? stuck on a log in screen and when login in as guest or with other O365 account of different organizations makes teams loading... Afterwards sign out and without any changes to my current real organization I can log in.... how is that even possible... 

This is the only thing that worked for me as well. You can delete the folders if there are there, but my Microsoft folder was not in the Application support folder at all. No Microsoft folders were. Make sure to fully quit teams first so there is no dot under the teams application, force quit if necessary.

Then I just went into my work/business Outlook calendar and clicked on a Microsoft teams meeting invite from earlier in the day, and then it launched the teams join a meeting window, and then I had to put my name in the teams join meeting window since it didn't know who I was, then I joined the meeting even though it was in the past. Then exited out of the active teams meeting window and then it prompted me to sign into Microsoft and then I just signed into my normal business Microsoft account and then everything just worked. No need for the personal sign in and then switch.

Hope this helps.

Yes, the above solution worked perfectly. Thanks CFS!

There is definitely a programming flaw in MS Teams application for Big Sur update however you may bypass this issue by simply following the above mentioned steps which is :

Step1 - Open any previous our upcoming TEAMS meeting invite from your calendar or emails.

Step 2 - The pop-up will prompt you to open the TEAMS application - allow.

Step 3 - It will prompt you to sign-in if you are the meeting organiser

Step 4 - Sign-in with your login credentials 

Step 5 - The pop-up will prompt for your permission to allow Camera and Microphone access.

Step 6 - You are all set.

Happy Teaming!