Access to folders in a group mailbox is only available through OWA (for now). Use the open to add a shared folder or mailbox (right click on Folders) and enter the email address of the group. OWA will then open the mailbox. There are some other settings that govern if group members have access to folders and rules. See https://office365itpros.com/2022/11/14/outlook-groups-folders-rules/

I have a group mailbox and we’ve configured to allow subfolders and rules. However, I still can’t see the subfolders in my Outlook app. Per your comment, we just need to open as a shared folder. How do you do that?

If you want access to all the folders in a group mailbox, use OWA to open the mailbox as a shared folder (yes, I know that sounds strange) and you’ll see everything.

Microsoft has announced (MC422161, August 29):

With this release, users will have the ability to create folders and organize content inside Microsoft 365 Groups mailbox using Outlook on the web.

Groups users will be able to create folders inside the Groups section in Outlook mail module. Users can move and copy messages across different folders inside of the Group. We are also releasing support for Rules inside Groups mailbox. With rules, users can automate the organization of incoming Groups mails. Once users have created folders, they will be able to view and access the deleted folder of the Group.

The feature should be available in late September and might solve your problem.

Hi Tony,

I am experiencing similar issues. We have a group folder for our HR function, which currently has +1,900 emails in it. We are finding that the group folder does not offer the functionality we need to be able to collaborate – namely, we would like to be able to create sub-folders and categorise emails based on the team member that has actioned these.

We were hoping to migrate the emails from the group folder over to a shared mailbox, however, from my research I have found that it is not as simple as it sounds. If I tried your option above, that being changing the group mailbox to a different SMTP and creating a new shared mailbox with the existing SMTP, would we be able to migrate the +1,900 emails over to the shared mailbox? If this is not possible (which I am almost certain it is not), would we still be able to access the group mailbox for history purposes?

Thank you so much in advance!

1. Create a new shared mailbox.
2. Assign a new SMTP address to the group mailbox.
3. Take the SMTP address previously assigned to the group mailbox and assign it to the shared mailbox.
4. All email sent to the SMTP address will now be delivered to the shared mailbox.

Hi Tony,

How do you go about doing that?

Yes , we need a license If the Shared mailbox size is over 50 GB. ( Ex: we just assigned a Microsoft 365 E3 license to the shared mailbox that increased the mailbox size to 100 GB)