Move mailbox contents to another mailbox

Brass Contributor

I have two mailboxes in Exchange Online. I want to move all the contents from one mailbox to the other. I tried using Outlook to do this, but things happen way too slow and Outlook crashes frequently. Both mailboxes have archives. The total amount that has to be moved is around 90GB. I tried using Search-Mailbox just on couple of items as a test and it worked. But I got a message that this cmdlet is retired. As well as New-MailboxSearch. So what is the Microsoft's way to do this simple task?

4 Replies

Hi @badsector ,

There're many ways to do that, ( one of them is what you already tried ). But let me ask a question...

Why move the content to another mailbox instead to rename/modify the existing one? 

Other point... You say that both mailboxes are online... But is your environemnt only EXO or do you have a hybrid one? ( In I hybrid one I'll have more ideas ).

For only EXO, I would say that the better solution would be to create a New-ComplianceSearch, export the PST and import it to the new mailbox, ( you'll need AzCopy ).


New-ComplianceSearch (ExchangePowerShell) | Microsoft Learn


Use network upload to import PST files - Microsoft Purview (compliance) | Microsoft Learn


Wish you a nice day :) 

Hi @FcoManigrasso,
The mailbox, that is currently being used by the end user, has a user account in a local AD. The one that needs to be migrated, is only in AzureAD. Besides both mailboxes have emails in them. We do have hybrid configuration and can move mailboxes from Exchange Online to Exchange Server. But will that do any good? In Exchange Server I can use New-MailboxExportRequest to export the contents to three .pst files. But I can do the same with New-ComplianceSearch. Is the former better than the latter? I was hoping that there's an easier way to do such a trivial task. Tossing huge .pst-s is anything but convenient. I don't even have that much free space on my computer.

Hi @badsector,


I was thinking about a New-MailboxRestoreRequest to the destination mailbox. ( I never did it that way but it should work ). So, softdelete the source mailbox and then restore it to the target one.


New-MailboxRestoreRequest (ExchangePowerShell) | Microsoft Learn


In your scenario, I would proceed with the Compliance search, ( it's a lot more effort but more secure from my point of view ). But again, it's up to you and there're the options :) 



Yes, New-MailboxRestoreRequest should work. I've used this before and it works. The problem is that I have to deliberately put a working mailbox in a "softdeleted" state. And I won't do this, unless I have exported the contents as .pst files as a backup. Exactly what I want to skip. It's unbelievable that there's no a simple solution with clicking buttons on a GUI for such an extremely trivial task.