Disable Outlook "Do not send response" meeting response option

 HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\Calendar

DWORD: ForceMtgResponse
Value: 1

 

You'll need to restart Outlook after setting this key.

Administrators can add the key using Group Policy.

 

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\Options\Calendar
DWORD: ForceMtgResponse
Value: 1