Shared mailboxes are used for all sorts of reasons. During migrations to Office 365 I get questions on how to use them and in particular how to license them. The good news is Microsoft makes shared mailboxes free in Office 365, however, there are a few things to be aware of if you plan to use them.
There is a great article on the support site about all of the specifics of shared mailboxes, so I won’t repeat all of that here (link to the article is below). But, I do want to point out a few things you need to be aware of and give some food for thought.
Migration is a great time to think through why you are using shared mailboxes. Office 365 has several team related offerings, like Groups and Teams, as well as SharePoint sites that offer a lot of the functionality that shared mailboxes are often use to provide. As you take up your migration, take a moment to consider the use cases and how you might improve those by moving to a more modern collaboration offering. Myself and the teams I work with have really latched onto Teams as a collab tool and love the integrations with a lot of the tools we use every day like Trello, OneDrive and others. It took our shared info to a new level, so check it out you might be surprised.
As I pointed out earlier, there is no cost to a shared mailbox in Office 365. But you do need to stay below 50GB for those, or you will have to pay for an additional user. For most people that isn’t a huge concern as on premise mailboxes tend to be well below that number. If you are thinking about rolling out encryption services, Microsoft does not support encrypting messages from a shared mailbox, so you will need to find a third party that allows that, or move to another method of sending.
One final note that I thought was interesting is a very direct statement that the Outlook mobile app doesn’t support shared mailboxes and never will. Maybe this is a safeguard to make sure people don’t abuse the free offering, but either way, watch out for this as you think about how you plan to access and use shared mailboxes.
Check out the link below for more info and instructions on how to create a shared mailbox in Office 365.