Best Practice and Steps for converting Regular mailbox to Shared Mailbox without any license?

Recently I have been in a situation where I have Exchange 2016 Hybrid Exchange Online. Exchange 2016 Active Directory DS is synched to Azure Active Directory using Azure Active Directory Connect Apps.


I am looking for the best way to convert the Regular licensed mailbox (Size less than 50 GB) into a shared mailbox without a license.

As far as I know, a Shared mailbox of less than 50 GB do not required any license assigned, but when I convert the mailbox from the Microsoft 365 portal and cancel the license, the mailbox is gone missing.

The same happened when I used PowerShell or Microsoft Graph to convert the Regular mailbox to Shared Mailbox using the Set-Mailbox -Type Shared cmdlet and then cancel the license. It goes deleted.


After lots of googling, I found the below solution.

First, Set the remote mailbox to shared On-premises with Set-RemoteMailbox.

Set-RemoteMailbox <user> -Type Shared

Let it sync, and verify the Microsoft 365 mailbox is shared as well.

get-mailbox <user> |FL *type* 

If it’s not set to shared, then it first needs to convert to a shared mailbox, confirm its set and then remove the license.


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Amit Singh

Amit Singh

I am a dynamic Tech Enthusiast, specializing in various Microsoft technologies, including Office 365, Exchange, PowerShell, and Active Directory. I loved to helped customers worldwide design, implement, migrate, and secure Exchange and Office 365 through various roles for different employers, and more recently, as an independent consultant.