In the current preview versions of Microsoft Teams there is no option to stop the program from starting up when your computer reboots however, we can disable this process so that you can manually start the program up when you need to use it.
Quick Tip: How To Prevent Microsoft Teams from Automatically Starting Up
In the current preview versions of Microsoft Teams there is no option to stop the program from starting up when your computer reboots however, we can disable this process so that you can manually start the program up when you need to use it.