Hi everyone !
Today I wanted to share a small tip if you want to disable team from using the domain upn when the session open for the first time.
The tip is nice as when the user open Team for the first time if you are hybrid / on-prem the users can have difficulty to open team as they need to select “use another email” in the windows footer. If the user don’t use the correct login then a loop happen, the sign-off seem impossible from Teams when it try to load an unexisting account. (Removing team and reisntalling it is the easiest workaround if it happen)
The tip can be easilly done by Group Policy.
The magic registry key to use in our case is SkipUpnPrefill (HCU\Software\Microsoft\Office\Teams)

You can create the settings are in GPP;

As you can see it’s a easy tip to do 🙂 (more read on the settings here; https://learn.microsoft.com/en-us/microsoftteams/troubleshoot/authentication/teams-defaults-to-domain-joined-account)
Thanks everyone