So we are migrating from 7.1.x to latest 8.0.3 and all is working great.

So this is why I am wanting to migrate more than once:

At this point, most of our employee mailboxes are filled with tons of stuff, each account migration is taking anywhere from 1minute - 30+ minutes. The president of the company I don't even want to think about how long that one will take.

If I start a migrate on the Presidents mailbox and it takes 2 hours to complete, what happens to the emails that were recieved within that 2 hour window? Are they lost? Does the migration wizard know to keep looking for new messages that arrive AFTER the migrate command has started and migrate them too?

I just want to make sure that when we enable 8.0.3 and kill our 7.1.x instance, that every-SINGLE piece of email is migrated. I don't want gaps, I don't want someone to lose all emails in the past X amount of time because the migrate couldn't catch them. Running a migrate again to get the deltas provides the error bulkprovision.EMPTY_IMPORT_QUEUE .

So I hope someone can clear up my confusion!

Goal: Migrate without losing a single email in the process, possible?