Three different things in Microsoft 365 give several people access to one email address, they look similar from outside and they behave nothing alike. Choosing the wrong one is why enquiries get missed and why nobody can tell who answered what.
The short version
- Distribution list — sends a copy to everybody. Good for announcements, useless for anything needing a reply.
- Shared mailbox — one real inbox everyone can see. The right answer for enquiries and support addresses.
- Microsoft 365 group — a shared mailbox plus a calendar, a SharePoint site and a Teams team. The right answer for a project or a department.
Distribution lists
A distribution list is a forwarding rule with a name. Mail sent to it is copied to each member's own mailbox and that is the end of its involvement.
There is no shared record. If four people receive an enquiry, four people each have their own copy, none of them can see whether any of the others replied and the classic outcomes are either four replies or none.
Use for: announcements, all-staff notices, a supplier list you email occasionally.
Never use for: anything a customer might reply to. This single mistake accounts for most lost enquiries in small businesses.
Shared mailboxes
A real mailbox with real storage, accessed by named people through their own accounts. Everybody sees the same inbox, the same read state and the same replies.
Two settings make the difference between one that works and one that does not:
Save sent items in the shared mailbox. Off by default in some configurations, which means replies vanish into the sender's own Sent folder and nobody else can see the conversation. Turn it on.
Send as, or send on behalf of. Send as makes the message appear to come from the shared address, which is right for a customer-facing address. Send on behalf of shows both names, which is right where the customer benefits from knowing who they are dealing with.
Licensing: no licence needed under 50GB, provided nobody signs into it as an account. That is the correct configuration anyway — members should use their own credentials so the audit log records who did what.
A shared mailbox that nobody owns is a queue that nobody works. The technology is fine; the rota is the missing part.
Microsoft 365 groups
A group is a membership list that several services use at once. Create one and you get a shared mailbox, a shared calendar, a SharePoint site and, if you want it, a Teams team — all with the same members.
That is the right shape for a project or a department, where the people involved need to share documents and a calendar as well as mail.
It is the wrong shape for a customer-facing enquiries address, because the group's mailbox behaves subtly differently from a plain shared mailbox and the extra services are clutter you then have to govern.
Note that every Teams team creates a group behind it, which is why unrestricted team creation produces an estate nobody can describe. There is more on managing that in this article.
Choosing, in three questions
- Will anybody reply to messages sent here? If no, a distribution list is fine. If yes, you need a shared mailbox or a group.
- Do the same people also need shared files and a calendar? If yes, a Microsoft 365 group. If no, a shared mailbox.
- Is it customer-facing? If yes, a plain shared mailbox with sent items saved centrally.
Where shared mailboxes stop being enough
A shared mailbox has no concept of ownership, status or deadline. It is a folder that several people can see. Past roughly two dozen enquiries a week, that stops scaling, and the symptoms are consistent:
- Nobody is sure whether an enquiry has been picked up.
- Two people reply to the same message.
- Something sits unanswered for four days and nobody notices.
- Nobody can say how many enquiries came in last month or how long they took to answer.
At that point the answer is a ticketing system or a CRM route rather than a better mailbox configuration. Enquiries get an owner, a status and a response time you can actually report on. That is CRM and automation work rather than an Exchange setting.
Tidy up what you already have
Most businesses have accumulated all three types over the years, often for the same purpose. Worth an hour: list every address that reaches more than one person, work out which of the three it is and check that the customer-facing ones are shared mailboxes with sent items saved centrally.
While you are there, check whether any shared mailboxes are needlessly consuming a paid licence — a common and easily corrected waste covered in the admin centre checklist.
If your enquiries currently land in a mailbox everybody can see and nobody owns, tell us how it works today and we will show you what routing them properly would look like.
