Office365 - create new Outlook profiles and sync data during mailbox migration?

I'm migrating a 16user Exchange 2010 environment to O365.
I'm going to use cutover method.

Probably a stupid question, but once I start the mailbox sync from Exchange to the user profiles created in O365, can I straight away create new Outlook O365 profiles and start re-syncing the data back for the users?

My aim with this is to have 99% of the data re-synced to the new O365 profiles in Outlook and have the data ready so the users can just get back to work without any downloading lag. That way the night before we go live, I do the final sync of the Exchange mailboxes to O365 and change the mx records, then have the users grab the last few 100mb in their Outlook in the morning.

Kind Regards
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Alan HardistyCo-OwnerCommented:
Absolutely - but you will need separate Outlook Profiles to be able to do that as Outlook won't like two email addresses that are the same in the same profile.


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moncompAuthor Commented:
That should be no problem to setup a new profile. Thanks for confirming :)
I couldn't think of any other way to reduce the downtime for the users! :)
Alan HardistyCo-OwnerCommented:
Do the users have large mailboxes?

What sort of Internet download speed do they have?

moncompAuthor Commented:
I have 65GB of email to migrate and re-sync. Internet connection is 4mb/4mb
Alan HardistyCo-OwnerCommented:
Doesn't sound too painful.  Your approach is a sensible one and should work happily so there is minimal downtime.

The sync may take a while (possibly a few days) to complete the initial pass, so plan on it taking a good week to complete the migration.
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