Same here at my company. We use Outlook Desktop app (version 2018). Uninstalled Teams Classic and installed New Teams today. The Teams meeting option in Outlook's new Appointment window has now disappeared and the AddIn no longer exists in Options>Add-ins (active or disabled). Even after various app restarts. Reverting back to Classic Teams does bring the addin back. We want to use New Teams though, so what can I do?
I even tried taking a copy of the Classic Teams' Microsoft.Teams.MeetingAddin.dll file and then registering this manually using:
C:\WINDOWS\system32\regsvr32.exe /n /i:user "C:\Users\<path to folder>\TeamsMeetingAddin\1.0.23270.2\x64\Microsoft.Teams.AddinLoader.dll"
And again, but trying the x86 path. Both times a message flashed up saying DllInstall succeeded. But alas, opening Outlook again I still can't see the Teams meeting add in option.
(red circle shows where it used to be on the appointment creation window):
