Office 365: Assign a Group to a Shared Mailbox

Question

Does anyone know if its possible to assign a group to a shared mailbox with Office 365? This seems to be possible with on-prem Exchange, based on the threads I've read, but I'm having issues with Exchange Online.

The GUI definitely doesn't allow it, but the following PowerShell command executes without an error:

Add-MailboxPermission -Identity "[email protected]" -User "security-group-name" -AccessRights FullAccess -InheritanceType All -AutoMapping $true

After I execute that command I can even go to the Exchange Online Admin Portal and under:

Recipients -> Shared

If I Edit the shared mailbox and go to "mailbox-delegation", I see the group name listed under "Full Access".

However, if I open Outlook and mount the shared mailbox, it won't let me list the contents.

I'm wondering if this is a timing / sync issue; or if this is truly not supported. Its been about an hour at this point and it still doesn't work in Outlook.

Solution

From my own experience and testing:

You can assign a group to a mailbox, but a few functions don't work, such as auto mapping of the mailbox.

This means that the user can access the mailbox, but they have to add it themselves.

Depending on how they add the mailbox, they can or cannot send mail from that mailbox.

If you, however, don't use groups, but assign users to the mailboxes, then it will work as intended.

Comments

[Doug]

thanks for responding. I've actually tried manually adding the mailbox and I'm still not able to load it. Hopefully its just a timing / sync issue and it will resolve itself soon; however at this point its been 1.5 hrs.

[LPChip]

You add the mailbox by going to file -> Add account -> enter email address. If it asks for a password, enter the password for the user account. If it then pops up with a login box with username and password, enter the email address of the user with their password.

[Doug]

No, I added from File->Account Settings -> (Select Account) -> Change -> More Settings -> Advanced -> Open Additional Mailboxes . I'll see if I can get it working the way you stated, thanks.

[Doug]

That method just errors out with a generic "Something went wrong"

[LPChip]

Its hard to tell if you did something wrong or that Microsoft changed something, given that this is how I've done it in the past. But that said, we stopped doing that because people not being able to send email or not getting the mailbox automatically in outlook is something we just can't have, so we either directly connect the mailbox in outlook as a primary account, or we grand users on a per-user base rather than group based.