Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi
I just had this happen to one of our IT guys.
Clearing the caches usually fixes this issue, but this time it was something unexpected.
Check Settings/Apps and see if you have both Microsoft Office 365 installed from the Microsoft App store and Microsoft Office 365 Apps for Enterprise installed via click to run.
If you do, uninstall the APP store version, it will be the one with the older date.
No restart required, launch Teams now and see if that is what was causing your issues with Teams at start up.
If Teams still doesn't install then stay in Apps and go to Teams and tell it to repair itself, the combination of both of those fixed it for us.
Take care