Exchange 2003 to Office 365 Migration


  • I have a client who needs to migrate an Exchange 2003 server to Office 365. They also want to do the AD syncing with Office 365. I need to know if I will be able to perform traditional mailbox migrations or is there some specific Office 365 migration tool for moving mailboxes? They want to decommission the Exchange server once they are moved over to Office 365 so they will be 100% cloud.

    Vincent Sprague

    Monday, January 28, 2013 7:04 PM

All replies

  • Yes, but you won't be able to use the PS, move-mailbox,or move-request functions within 2003 to deal with e-mail itself, which is a bit of a pain.

    1. Get the O365 portal up and working and verify your domain(s)

    2. Install the DirSync, FIM, PS tools, patches, and all the other co-existence tools on a separate Windows 2008R2 and get that working. Run the necessary PS commands to get all the permissions in place.

    3. You should see the accounts appear in the O365 portal with a sync icon next to them. That means, they are being synched from your AD. If you enabled the SSO option, the passwords should be the same as well.

    4. Assign the users to a service plan in the O365 portal. Set up FOPE.

    5. Switch the DNS, profiles and such over to O365.

    6. Copy their old mail into their new mailboxes via some back-end process and/or manually exporting/importing PSTs. Done.

    One catch to beware of is...MS apparently throttles the migration bandwidth. Large existing mailbox PST's may take DAYS/WEEKS (not kidding) to successfully update all older e-mail.

    You still may want to consider dropping an Exchange 2010 server into the mix and just using the built-in move-request features to merge the mailbox data. Much easier.


    • Edited by ABCFED Monday, January 28, 2013 7:45 PM
    Monday, January 28, 2013 7:43 PM
  • If I migrated to Exchange 2010 first then I could use the standard move-request functionality to move mailboxes into the Office 365 environment? Is that throttled as well? I have some mailboxes that are about 16gb in size. You also mention some back-end process for moving mailboxes from 03 to Office 365. By that do you mean a Microsoft back-end process or some 3rd party software.

    Vincent Sprague

    • Edited by Baron164 Monday, January 28, 2013 7:57 PM
    Monday, January 28, 2013 7:51 PM
  • Hi Vincent,

      I may be a bit late but I just used as suggested by AT&T O365 and it was priceless, especially since the migration took several days to complete I was able to do several Delta (differential) passes with just a couple clicks. It is well worth the low cost per mailbox, I had several over 10GB.



    Tuesday, February 05, 2013 6:46 PM