EWS : Appoitnment Item.Id.UniqueId is not constant

Question

There is a weird problem I\'m facing when working with EWS Managed API 2.0 with Exchange Server 2007 SP3.

When I create an appointment and I save it, I get its ID us

Answer 1

This is Actually a very common problem faced by those who are using the EWS Managed API.
For some reason (I do not know why) the Unique ID changes when the appointment is moved to another folder.
You can find your question and your answer in my post here:
Exchange web services: why is ItemId not constant? [continued]

Answer 2

Keep in mind that Outlook recreates appointments when it processes incoming calendar updates.

Answer 3

Appointment itself doesn't have unique id which doesnt change, but appointment has property ICalUid (i think its Unique calendar item id):

appointment.ICalUid;

which is really unique and doesn't change then meeting is updated as far as i tested.. i generated 1000 meetings for one person and all ICalUid's were unique. Try it, it helped for me :)