In the previous issue of Exchange Messaging Outlook, I explained how to use group policy to disable the tentative response option. The July 3 2018 Outlook 2016 update builds in the ability to remove the Do not Send a Response option.

The required update is in Outlook 2016 Click to run and is now available in the volume licensing version when the July 3 2018 Outlook 2016 update is installed.

To hide the Do not Send a Response option, add the DWORD ForceMtgResponse to the following registry key:

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

Do it for me

If you don't want to edit the registry yourself, you can download and run a rready-to-use registry fil e to set the key.
ForceMtgResponse GPO ForceMtgResponse

Outlook 2013

In Outlook 2013, the only option is to disable the menu option, adding the CommandID to the key at

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\x.0\Outlook\DisabledCmdBarItemsList