This question is pretty technical and might require some expert knowledge regarding the server behaviors. With exchange server 2007 SP1, when I try to retrieve bunch of emails, the sync key will be incremented by 1 for each retrieval. However, occationally server somehow sends same sync key which indicates that there are no more emails to retireve. However, when I check inbox using OWA, there are still a few emails left. and consequently, when I try to sync inbox manually after such occurance, server replies that there are more items to sync, but when actual sync starts same thing happens again (server does not give leftovers) has anyone faced this kind of problem before? If this is known bug with MS Exchange, please let me know. Thx