This article identifies situations that can result in contacts being duplicated on the server.

I. This situation involves existing contacts that reside in an Address Book (category) on the server that has not been selected for processing by NotifyLink.  If you create a contact on the device with the same first and last name as the contact on the server and assign it the same Address Book (Category) as on the server, NotifyLink will not update the server contact.  It will create a new contact on the server resulting in a duplication.

II. Another situation that creates a contact duplication:  When the Category (Address Book) of a contact is changed on the device, the contact is created in the new Address Book, but also remains in the original category on the server.