User Configuration > Administrative Templates > Microsoft Outlook 2016 > Account Settings > Internet Calendars
User
HKCU\software\policies\microsoft\office\16.0\outlook\options\webcal
By default, Internet Calendars are available on each client that the users use to connect to their Microsoft Exchange Server mailboxes. This setting allows you to disable roaming Internet Calendars. When roaming is disabled, Internet Calendars are available only on the client that originally linked them.