Hi @Mark Cooper ,
If you cannot get the Teams Meeting Add-in for Outlook to install, you can download and run the Microsoft Support Recovery Assistant to perform automated troubleshooting steps and fixes, or you can try to follow this links steps to manually to fix it:
Please make sure the add-in is not disabled in Outlook 365. If you still don't see the add-in, try to follow these steps:
Launch RegEdit.exe
Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Addins
Verify TeamsAddin.FastConnect exists.
Within TeamsAddin.FastConnect, verify LoadBehavior exists and is set to 3.
If LoadBehavior has a value other than 3, change it to 3 and restart Outlook.
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