User Configuration > Administrative Templates > Microsoft Outlook 2016 > Outlook Options > Preferences > Calendar Options > Recurring item configuration
User
HKCU\software\policies\microsoft\office\16.0\outlook\options\calendar
This policy setting allows you to specify the default number of days after which a recurring meeting or appointment (but not a task) ends. If you enable this policy setting, the “End by” setting is the default setting for recurring meetings and appointments, and the “End by” value is set to the specified number of days after today’s date. For example, if you specify a value of 180 and today's date is May 5, 2011, the “End by” value is November 1, 2011 (180 days after today’s date). If you disable or do not configure this policy setting, the “No end date” option is the default setting for recurring meetings and appointments.