Hi,<BR><BR>I am having a bit of trouble synchronising users calendars. The explanation is a bit long please bear with me.<BR><BR>I have an application that creates Appointments in users calendars. Once created it stores the objects ID with the meeting in a db table.<BR><BR>I also have a page that syncs users calendars with the DB. This is done by running through each users calendar and checking that each appointment is in the db table by comparing the Objects ID. The problem I am having is that every AppointmentItem in the users calendar has a different ID. So if you create an appointment with five recipients each recipients appointment will be assigned a different ID. This means that I need to find the "parent" appointment item when I come across an appointment in a users calendar. <BR><BR>So far I have checked the sender or organiser of the appointment, logged into their calendar and searched for appointment but I can&#039;t find a reliable way of checking that the original appointment I worked with and the orginisers appointment is the same. I have tried the IsSameAs command which works sometimes but not all the time.<BR><BR>Any help much appreciated.<BR><BR>Matt