Make Outlook the default program for E-mail, Contacts, and Calendar
Supported on: At least Windows Server 2008 R2 or Windows 7
Registry
software\policies\microsoft\office\16.0\outlook\options\general Value name: check default client
Enabled: check default client = 1
Disabled: check default client = 0
Description
This policy setting controls whether Outlook is the default program for e-mail, contacts, and calendar services. If you enable this policy setting, the "Make Outlook the default program for E-mail, Contacts, and Calendar" check box on the General tab of the Office Center is selected and users cannot change it. If you disable this policy setting, users cannot make Outlook the default program for these services. If you do not configure this policy setting, Outlook is made the default program for e-mail, contacts, and calendar services when it is installed, although users can designate other programs as the default programs for these services.