If Microsoft teams continue to reinstall on their Windows PC and start at startup, there is a solution. You can not uninstall Microsoft Teams as usual: you must uninstall it twice.
It's silly, but that's how it works. In particular, you must uninstall both "Microsoft Teams" and the "Team Machine-Wide Installer". If you only uninstall the Microsoft Teams application, it will be reinstalled by the machine-wide installer every time you log in to your PC. To completely uninstall teams, you must remove both applications.
To uninstall both apps, go to Settings> Apps> Apps & Features on Windows 1
Under Apps & Features, search for "Teams". Uninstall both Microsoft Teams and Teams – Machine-wide installer.
You can also uninstall these applications through the classic Control Panel. Go to Control Panel> Programs> Uninstall a Program, search for "Teams" and uninstall Microsoft Teams and Teams Machine-Wide Installer.
You're done! The next time you log in to your PC, the teams will not automatically reinstall themselves. It remains deleted from your system until you intentionally download and install it.
As noted on the Microsoft website, teams are also uninstalled when you uninstall Office from your system. In many cases, Microsoft Office appears to automatically install both teams and the machine-wide Team Installer.