Sometimes it is required to prevent late joiners to important meetings. There is nothing worse as a presenter to be interrupted mid presentation by automated messages that someone has entered the meeting, or worse, someone apologising for being late!
Now you are able to lock your Teams meeting when you are ready to begin. When locked, no one else will be able to join that meeting. However, they will still be able to join the meeting chat (if enabled) and view the recording post meeting.
How to Lock Your Teams Meeting
When in a meeting, open the participants settings and then click the ellipsis (…) next to the close icon on the blade

From the drop down list, click “Lock the Meeting“

Confirm the lock to activate it.

Anyone attempting to join the meeting will now be met with the following error

Unlocking a Meeting
If you do need to unlock the meeting you can do so by turning back to the menu where you locked and clicking Unlock Meeting