How to mark a To-Do as completed? 02 September 2015 06:16 Updated Please start in the 'Agenda' section. After To-Do is completed click the check box To unselect a To-Do activity click on the selected check box Related articles What is the difference between Act! 365 and Act! Growth Suite Starter? How to add a note to an activity How to clear completed To-Do's What is included in iCal export? How do I record an activity from a contact?