Guide · Microsoft 365 and Outlook

Outgrowing a Microsoft 365 shared mailbox.

Most small teams on Microsoft 365 answer clients from a shared mailbox in Outlook, and for a while it works. This guide covers the signs it has stopped working, what to keep when you move on, and when a shared mailbox is still the right tool.

Microsoft features checked against Microsoft Learn · October 2026

Where you are now

How a shared mailbox works

A shared mailbox is one address, such as support@ or accounts@, that a group of people in your organisation can open from their own Outlook. It is a sensible place to start:

  • No extra license. A shared mailbox stores up to 50 GB without a license of its own. Each person who opens it needs their own licensed mailbox.
  • Permissions, not passwords. People get Full Access to read and manage the mail, plus Send As or Send on Behalf to reply. With Send As, replies look as if the mailbox sent them; with Send on Behalf, they read "Sam on behalf of Support".
  • Inside your organisation only. Microsoft supports up to 25 users on one shared mailbox, and people outside your organisation cannot be given access.
  • Everyone can delete. There is no way to stop a member deleting a message from the shared mailbox.

Provider reference: Microsoft Learn: about shared mailboxes

Provider reference: Microsoft Learn: shared mailbox permissions

The signs

Seven signs you have outgrown it

A shared mailbox solves who can read the client address. It does not say who is handling each email, group work by client, measure how long clients wait or remember what you are waiting on. These are the moments that show it.

  • 01Read means nothingRead and unread belong to the mailbox, not to you. Once anyone opens a client's email it stops being bold for everyone, whether or not it was answered.
  • 02Two people replyNobody can see that a teammate is already writing, so the client gets two answers, sometimes different ones.
  • 03Nobody owns itCategories and flags say what a message is about, not whose job it is. The phrase you hear most is "I thought you had it".
  • 04Nobody knows who answeredWith Send As, every reply looks as if the mailbox sent it. When a client calls about an answer, you search Sent Items to find out who wrote it.
  • 05No history per clientTo see what a client asked for last quarter you search by sender, and miss everyone else at their organisation who wrote in.
  • 06No promise you can keepNothing tells you a request has waited two days for a first reply until the client follows up to ask.
  • 07Waiting on the client, from memoryWhen you need a document or an answer from a client, the only reminder is a flag on someone's copy of the thread.

If several of these happen every week, the shared mailbox has become the bottleneck.

What changes

What a service desk adds

In Tend each email becomes a request with one owner and a status, and the inbox is the team's shared list of them. The seven signs above each have a plain answer:

  • Owner and status. Every request is open, in progress, waiting or resolved, and has one owner or is visibly unassigned. Opening it does not mark it done.
  • One reply, not two. Tend warns you when a teammate has the same request open.
  • Who said what. Every reply on a request shows which teammate wrote it. Each queue chooses what clients see: your company name, the agent's name, or "Sam at Harbourline".
  • History per client. People are grouped into organisations by their company email domain, so a client's page shows every request from everyone there.
  • Response targets. Each queue has a first-reply and resolution target in business hours, and late requests show how late.
  • Document requests. List what you need from the client on the request. Tend shows it on their tracking page and chases it by email every 3 days until it arrives.

What to keep

Keep the address your clients already use

The address is the one part of your support your clients have learned. It is on your website, your invoices and in years of threads. Changing it costs you requests sent to the old one, so keep it.

Keep the shared mailbox too. It needs no license up to 50 GB, and forwarding leaves its own copy in place, so it stays the archive for everything before the move and a backup of everything after it. Calendars, Teams and personal mail stay in Microsoft 365 as they are. Only the handling of client requests moves.

Step by step

Move to Tend without changing the address

Allowing the forward and setting it up are covered click by click in the Microsoft 365 forwarding guide.

  1. 01Start a free trial. You confirm your email and name your workspace, and it opens with a Support queue ready to receive email.
  2. 02Invite the people who answer clients in Settings > Users. Each one who answers takes a seat. Clients never do.
  3. 03Decide how new requests find an owner. In Settings > Queues, a queue can land requests unassigned for the team to pick up, give them to one person, or use round-robin between agents.
  4. 04In Settings > Email, copy your queue's private address from its card.
  5. 05Ask your Microsoft 365 admin to allow external forwarding for the shared mailbox alone, then forward it to the private address, keeping a copy in the mailbox.
  6. 06From an outside address, such as a personal account, email the shared address. Check the new request shows that sender as the requester, then reply from Tend and reply again from the outside account.
  7. 07Agree one rule with the team: client email is answered in Tend, not in Outlook. A reply sent from the shared mailbox never reaches the request, so nobody else can see it.
  • If a client gets a bounce containing 5.7.520 Access denied, external forwarding is still blocked. The forwarding guide shows the policy that fixes it.
  • Optional: in Settings > Email, verify Your sending domain so Tend's emails go out from your own domain.
  • Share your client portal link when you are ready. Clients sign in with an emailed link, with no password to create, and see where each of their requests stands.
  • Once Tend has run for a week or two, remove Send As from people who no longer need to answer from the shared mailbox, so replies do not slip back into Outlook.

Honestly

When a shared mailbox is still enough

A service desk is one more tool to pay for and learn. A shared mailbox is still the right call when most of these are true:

  • One or two people answer clients, and they can see each other's work at a glance.
  • A handful of requests arrive each week, and most are settled in a single reply.
  • Clients do not expect a stated response time, and nobody asks you to report on one.
  • You never need to know who answered a client, how long their requests took, or what you are waiting on from them.

If that is you, stay where you are and come back when the signs above start to show.

Good to know

Questions, answered

Do our clients need to change anything?
No. They keep emailing the address they already use. Tend's emails go out under your queue's name, and when a client replies, the reply comes back to the same request.
Will our old Outlook conversations move into Tend?
No. Tend does not import Outlook history. Leave the shared mailbox in place as the archive for everything before the move; new email, and replies to it, start in Tend from the day you forward.
Should we delete the shared mailbox afterwards?
No. A shared mailbox needs no license up to 50 GB, so keeping it costs nothing. It stays the archive, and forwarding keeps a copy of everything that arrives after the move too.
Can we keep using Microsoft 365 for everything else?
Yes. Tend only receives what you forward to it. Personal mailboxes, calendars, Teams and documents stay exactly as they are.
Can clients see each other's requests?
No. Each client signs in to their portal with an emailed link and sees their own requests. You can choose to let an organisation's owners, or everyone at that organisation, see all of its requests.
What does it cost?
US$29 per agent per month, plus GST for Australian customers. Clients and portal users are free. Every workspace starts with a 14-day free trial, no card required.

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