If you have an issues where the Teams Add-in will only work in Outlook if you open Teams first, then open Outlook while using UPM

Add "Software\Microsoft\Office\Outlook\Addins" to Registry inclusion list

Note: Be aware that by policy definition on setting "Profile Management\Registry\Inclusion list":   if the setting is enabled, only keys on this list are processed.

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Problem Cause

UPM is not syncing the Registry location for the Add-in, which is why it only works after opening Teams first as it is automatically created at that stage