I am in the middle of an Active Directory migration, during the last phase I will be migrating the user accounts and mailboxes, all at the same time, over a long weekend.
My plan is to run the Prepare Move Request script in exchange 2010, then migrate the accounts with the ADMT tool and then move the mailboxes.
At a some point during that weekend I will need to forward incoming emails to the new server versus the old.
My question is just at what point? Do I need to wait until all mailboxes have finished moving?
I am planning on "SuspendWhenReadytoComplete" and then complete them all, but I am not sure at what point I will be able to start receiving emails into the new mailboxes. I want to allow the users to access their emails for as long as possible during that weekend, or have the shortest down time as possible.
Also any tips you can provide to deal with active sync and anything else you can thin of will be welcome.