So I discovered that there is the right way and the wrong way to create a Shared Mailbox when using Office 365 Exchange Hosted and Exchange 2016 in a Hybrid configuration. So the way I would normally do it would be to migrate the mailbox to Office 365 and then click that pretty little button to convert to a Shared Mailbox.
It turns out that when you do that it will create the mailbox as a shared mailbox, however the Active Directory (AD) Components are non-existent. Which means you cannot assign permissions to users who are synced by AD.
Well…. you can…. but it doesn’t actually work.
So what can we do to make it work when you have a user who is complaining that they need to send out a file at 4:45 PM on a Friday???
Well there is not much that you can do, but I would start with converting the mailbox back to a normal user mailbox and then migrate the mailbox back to your Local Exchange Environment.
Once the migration is complete you can then run the following command to convert a normal user account to a Shared Mailbox on Exchange.
Set-Mailbox AJones -Type shared
Once the command is complete (which is really freaky fast) you will then be able to see the mailbox under the “Shared Mailbox” section in Exchange.
I would then Migrate the mailbox back to Office 365 the way that it is and once it is done you should be good to go.
In the event that you would want to switch the Shared Mailbox back to a normal mailbox, here is the command to switch it back.
Set-Mailbox AJones -Type regular
I hope you found this guide helpful, and if did, please share it with your friends.