Hi! have created a retention policy retaining content forever and included All Office 365 Groups. Upon deleting documents in the corresponding SP Team Sites, they are stored in the Preservation Hold Library as expected. But Group members are still able to delete conversations and when they do I have no idea where conversation messages go or how to recover them.
Thanks for your reply. I'm afraid I don't know how to find this "hidden" folder. As an admin I'm able to open the Office 365 Group shared mailbox but the Deleted Items folder is empty despite the retention policy. If i click Recover deleted items I get the message "We didn't find anything to show here."