How to Merge/Consolidate Exchange Online mailboxes?

Iron Contributor

We're in the process of moving a lot of users from a cPanel-based email server (dovecot server). Since cPanel-based email server does not support email aliases, multiple user accounts were created for the same person.


So, for example, John Doe had:, and (Please don't ask me why they needed that many! lol)


Now, we'll be doing a mass transfer of all the email accounts from the dovecot server to Office 365/Exchange Online. So, each email will have a new account in Office 365. However, after the transfer we would like to merge all the email addresses for the same person, along with their emails, contacts and calendars, and then assign aliases.


How can this merging be achieved? (without using Outlook 2016 to copy each email account's mailbox)


Thanking you,

7 Replies

Hi Haneef,

You can use third party tools to do that, you can merge accounts in the destination.


Hi Nuno,


Thanks for that.


Will those 3rd party software merge the mailboxes in Exchange Online itself or will it merge on a local machine and then upload it?


Can you suggest me some names for both options please?


Thanking you,


Hi Hannef,


It merge to the destination, Ex (You have 3 source email and one destination mailbox). For those 2 options you have Bittitan, among others.

Thanks for that.


I just had another idea based on a suggestion in another forum.


Create with aliases and Then in the IMAP import job, use new rows to import these mailboxes.


Will Exchange Online recognise that these email addresses are aliases of the same account and import the emails accordingly?



Hi Haneef,


With third party it will work with IMAP import job could not work, because it match the primary smtp address unless you change it in different jobs.

Thanks for that information.


I also wanted to ask, this support article only has 3 columns in the example: Migrate other types of IMAP mailboxes to Office 365


However, I would like to know, if it is possible to migrate a source email address to a different destination email address and a subfolder within that? So, that would mean additional columns: DestinationEmailAddress, DestinationSubFolder




Hi Haneef,


No with that tool is not possible.