Changing Synchronization Modes and the Project Calendar
Project Management and Microsoft Project use a separate calendaring system for their projects. If the synchronization mode is Project Management-controlled, the Project Management calendar is used. If the synchronization mode is Microsoft Project-controlled or shared control, the Microsoft Project calendar is used.
If the synchronization mode of a project is changed from Microsoft Project-controlled or shared control to Project Management-controlled, the Project Management calendar is used. However, if the synchronization mode of a project is changed from Project Management-controlled to Microsoft Project-controlled or shared control, the Project Management calendar is still used. If you want to use the Microsoft Project calendaring system, you must manually change to the Microsoft Project calendaring system.