I am in the process of transitioning from Exchange 2003 SP2 (Ex2k3) to Exchange 2010 SP1 (Ex2k10) and have so far achieved the following:-
(1) Ex2k10 is installed & opertaional (normal)
(2) Majority of the mailboxes are still on Ex2k3 server, few mailboxes are on Ex2k10
(3) DNS server has following entries:-
- autodiscover.mycomp.com 192.168.1.11
- legacy.mycomp.com 192.168.1.10
(4) Clients are a mix of Outlook 2003 & Outlook 2010
Ex2k3 server, IP: 192.168.1.10, FQDN: mail.mycomp.com
Ex2k10 server, IP: 192.168.1.11, FQDN: exch.mycomp.com
If i try to configure a new profile (even for a user residing on Ex23k server) i get below error message:-
"The address list cannot be displayed. The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action."
This happens when i try to open the GAL, this user can still send/receive emails.