EWS create an appointment in Outlook Calendar but also created the appointment in Deleted Items folder

I am using VB.Net and EWS Managed API to create appointments in Ex开发者_JAVA技巧change 2010. When i call the "Save" method, an appointment is also created in the "Deleted Items" folder in the Outlook. Why is it the appointment is created in the "Deleted Items" folder? How do i avoid the appointment created in the "Deleted Items" folder? Thanks.

I use below code to save an appointment in the Outlook Calendar:

appointment.Save(SendInvitationsMode.SendToAllAndSaveCopy)

I think I've found the cause of it. There is an option in Outlook "Delete meeting requests and responses that have been updated".

When I unchecked this option, the appointment created will not appear in the "Deleted Items" folder.

I think it is also related to the AutomateProcessing of the Exchange, I guess EWS as the default of AutoUpdate.