I have a hybrid Exchange deployment between on-premise Exchange 2010 (SP3) and Office 365. I am able to successfully migrate on-premise users to the cloud, and everything works correctly.

However, if I create a new AD user, sync it via DirSync and activate it on the cloud, the on-premise Exchange will completely ignore it. It will not appear in the GAL, and Exchange will even be unable to deliver mail to it.

Thus far, the only way I've found to make this work is to create an on-premise Exchange mailbox for the new user and then migrate that mailbox to the cloud; but this process is cumberstome and basically stupid, and I sincerely hope there is a better way to handle it.

What is the proper way to handle the creation of new users in a hybrid Exchange deployment?


There are also commands such as "New-RemoteMailbox" and "Enable-RemoteMailbox" which can be run from OnPrem powershell (Exchange Shell) to create a 365 mailbox directly on the cloud while also associating it to an AD Account.

Check it out.


The only way to do it is by creating the user with the mailbox On-Premise and then migrate it.


I do not believe it is possible... DirSync works only in one direction so your 365 created mailbox will not appear in on-prem GAL. As you mentioned - your method is the only way (create mailbox on-prem then sync to 365), sorry...

  • +1, and to add to that I would script the whole process, powershell is very powerful nowadays. I'm not involved with the process, but our Sr MS Admin here has migrated several hundred users over the past several months, these users already existed but next year we'll be doing the same thing, and it's the same process as the OP mentioned. The good news is the mailbox is empty, so it doesn't take that long! Try syncing gigabyte mailboxes instead.... – MDMoore313 Dec 19 '13 at 12:47

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