I've been doing exchange2003 mailbox moves for years and never seen this behavior. I'm urgently moving 200+ clients off of a troubled mailbox store onto a newly built server, both Ex2003 SP2/WinSrvr2003 SP2. Circular logging is turned on on both source and destination servers. I had moved 10 of 12 groups of users and each time the move worked as normal - which means the session established connection to the destinaton and began migrating data after a couple of minutes. 10 sessions over a 6 days went this way. On session 11, the moves sat at "opening source mailbox" for hours and hours (7 or 8) then began and finished as normal although they took hours to complete. Before the connections were immediate and finished within 4-5 hours in most cases (we have a lot of 1gb+ sized accounts). Before I start the last session I hope to find guidance on why the delays are so so long. I see no errors or indicators in the event log. Network performance is the same as before. I appreciate any guidance or troubleshooting steps.

Hi Lot of reasons are there 1. Mailbox Size does impact on the bult mailbox move 2. May be corupted entries found bull in number on the session 11 mailbox move 3. During that time, any other database maintenance activity may run at the back ground 4. Backup may run at that time.