We are in the midst of finishing up our Exchange 2003 to Exchange 2010 Cross Forest migration. The way email flows with migration is that it comes into the Exchange 2003 domain and looks for a user, if it does not find that user it forwards to Exchange 2010. I've been noticing that emails are queuing up on the Exchange 2003 awaiting for delivery to the Exchange 2010 domain. When I attempt to unfreeze these messages it does not seem to do anything. Emails will eventually get delivered within 8-10 minutes. Is there a way to speed this up or is this something we just have to live with until we've completely migrated everyone over to Exchange 2010? Thank you~!Jeff D

How are you doing the forwarding, it's not using the SMTP virtual server is it? You should be using an smtp connector.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Yes we are using a SMTP connector, do you know of any way to optimize it on Exchange 2003?Jeff D

Hi doeweb, Could you please check the smtp log on the exchange 2003 server? If there are some information, please post here, we could do more research about the issue. That means we could check the deliver mail flow to confirm which step the delay occurs at. Per your description, you are using shared SMTP address space in the two forests. So, which methods do you use for the sharing? As below referred? http://support.microsoft.com/kb/321721 I would suggest that you publish the exchange 2010 emails system, and relay the email for exchange 2003 through exchange 2010, such as create a internal realy accept domain. Regards! Gavin TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.