We are a child domain within a larger domain. Our address book lists our users correctly. Our parent domain's address book shows several users with multiple entries. When a user in the parent domain tries to send an email to one of these users it is kicked with the duplicates user error message or an undeliverable error message. One of the users that is duplicated is no a user within our domain but he still shows up in the parent domains address book. Exchange 2003 is in use. Anybody have any ideas? Thanks

Hi How are these lists built? Have they included contacts? In that case, maybe the address isn't spelled correctly?Jonas Andersson | Microsoft Community Contributor Award 2011 | MCITP: EMA 2007/2010 | Blog: http://www.testlabs.se/blog | Follow me on twitter: jonand82

Hi Can you post NDR ? Can you try to send email to all his email address? Maybe there aren’t necessary records of local DNS.

Hi Do you have anything to update ?