User with 2 Mailboxes

Question

We're busy setting up our hybrid environment (Exchange 2010 onsite and Office365 Education), and we're having one problem:

When we setup the tenant in Office365, I used my work email adress as initial admin account. By now we have setup AD Sync and the hybrid environment, but now I have 2 mailboxes with the same account - One on Office365, and my "old" mailbox (with years of mails) on our Onsite Exchange server. Both Mailboxes are linked to the same useraccount which is synced via AD Sync.

How can I either "merge" the 2 maiboxes or delete the Office365 Mailbox in order to then migrate my existing mailbox?

Thanks

Sassan

Answer 1

Hi Sassan,

Any updates on your side? Please let us know if you need further assistance.

Thanks,

Jason Jiang

Answer 2

Hi Sassan,

Currently, it is not feasible to merge the two mailboxes directly.

As a workaround, we can manually backup the Office 365’s mailbox via the PST file and import into the local mailbox.

Export and import PST files in the Outlook client:

https://support.office.com/en-us/article/Export-or-back-up-messages-calendar-tasks-and-contacts-d791fe88-5c67-44c5-a3f6-a484508082a1

https://support.office.com/en-us/article/Import-Outlook-items-from-an-Outlook-Data-File-pst-345ad0da-7bc0-4a02-9cb7-2d1cf48ba8e3

After doing that, you can delete the account completely with the following PowerShell:

1. Connect PowerShell to Office 365 by referring to:

http://technet.microsoft.com/en-us/library/jj151815.aspx

2. Remove-MsolUser -UserPrincipalName *** Email address is removed for privacy *** –RemoveFromRecycleBin

Then you can re-sync the account and move the mailbox from on-premises Exchange to Office 365.

Thanks,

Jason Jiang