Hybrid exchange and shared mailboxes on-prem

New Contributor

Hey folks, can someone from MSFTs confirm that shared mailboxes cannot be hosted on-premise if we installed the Hybrid key?


Here it states, "any mailboxes" quote

If my organization is Hybrid with Microsoft 365 and I do not host mailboxes on-premises, do I still need to license Exchange Server?


If you do not host any mailboxes on the servers used to connect to Microsoft 365 you can license them using the Microsoft 365 Hybrid Configuration Wizard (HCW) which you can find here.

So I'm curious and my Bing-fu skills failed to get an answer. Anyway, it can help in the future next pals who will encounter the same question.




1 Reply
best response confirmed by Dima Razbornov (New Contributor)

@Dima Razbornov 


OK, the 2016 Hybrid licence key is provided by Microsoft on the provision that you do not host any mailboxes on that 2016 hybrid server.  If you were to host any mailboxes on that server, then you would need to acquire an Exchange 2016 licence.


Are you just using Exchange 2016 as the hybrid server?  Do you have other Exchange 2010 or 2013 servers in your environment?  If so, then shared mailboxes may be hosted on those servers no problem in a hybrid coexistence.


I always recommend migrating any shared mailboxes to Exchange Online alongside any logical groups of user mailboxes that you are migrating to the cloud.  Best to keep groups and teams in the same environment where possible as it works much better.