How to open and use a shared mailbox in Outlook

What is a shared mailbox in Outlook, and why use one?

A shared mailbox is a single email account that several people can open and work from together, using a common address like support@, sales@, info@, or billing@. Nobody logs into it with a separate password. Instead, your administrator grants a group of people permission to it, and from then on each of those people can read the incoming mail, reply to it, and send new messages from the shared address, all from inside their own Outlook, signed in as themselves. It is Microsoft's standard answer to the very common need for a team inbox that everyone can see and respond to without juggling a set of borrowed credentials.

If your company runs a help desk, a sales line, an HR address, or any general-purpose inbox that more than one person needs to staff, a shared mailbox is almost certainly what you have been handed. It is also what an admin sets up when an employee leaves and their mail needs to stay reachable, or when a department wants one face to the outside world rather than a scatter of personal addresses. The appeal is simple: shared mailboxes in Exchange Online have no license of their own when used normally, everyone works from one consistent address, and access is controlled centrally by an administrator rather than by passing a password around.

This guide walks through the whole thing end to end, for the two groups who search for it most: the person who has just been told they now have access to a shared mailbox and needs to actually open it, and the team or admin setting one up for everyone. We will cover how a shared mailbox can appear automatically through auto-mapping, how to add one manually in new Outlook and on the web, how to do it in classic Outlook including opening another person's folder, the all-important difference between sending as the shared address and sending on its behalf, how to make sure your sent mail lands in the shared mailbox instead of your own, what an administrator has to switch on, how this works on phones, and what to do when the mailbox stubbornly will not show up or will not let you send. By the end you will know exactly which path applies to your version of Outlook and your permissions.

Before any of the steps below will work, one thing has to be true: an administrator must have granted you access to the shared mailbox. This is the single most common reason people get stuck, so it is worth saying plainly at the top. You cannot add a shared mailbox to your Outlook just because you know its address. Permission is granted on the server, by someone with admin rights in Microsoft 365 or Exchange, and until that has happened, every method in this article will simply fail to find the mailbox or refuse to open it. If you are a regular user, the prerequisite is a quick request to your IT team; if you are the admin, we cover exactly what to grant in the permissions section further down.

It also helps to know which Outlook you are actually using, because the steps genuinely differ between them. There are, in practice, three Outlooks in 2026: new Outlook for Windows (the rebuilt app that Microsoft has been rolling out to replace the old one, with a toggle that says "New Outlook" in the top corner), classic Outlook for Windows (the long-standing desktop application, part of the Microsoft 365 or Office suite), and Outlook on the web (the browser version at outlook.office.com or outlook.com). New Outlook and the web share almost identical menus, because new Outlook is built on the same foundation as the web app. Classic Outlook is the odd one out, with its own older menus and, importantly, its own automatic behavior. Figure out which you have before you start, and the right path becomes obvious.

How does a shared mailbox appear automatically (auto-mapping)?

The happiest path is the one where you do nothing at all. When an administrator grants you Full Access to a shared mailbox in Exchange Online, a feature called auto-mapping is normally turned on by default. Auto-mapping tells Outlook to discover the shared mailbox on its own and add it to your folder list automatically, so the next time Outlook syncs, the shared mailbox simply appears in the left-hand folder pane underneath your own account, with its own Inbox, Sent Items, and folders ready to use. There is no setup on your end. You open Outlook, and there it is.

Auto-mapping has historically been a feature of classic Outlook for Windows, and it is the reason long-time Outlook users are used to shared mailboxes "just showing up" after they get access. If you are on classic Outlook and an admin has recently added you to a shared mailbox with the default settings, the most likely outcome is that you do not need any of the manual steps below. Close Outlook completely, reopen it, give it a minute to sync, and look for the mailbox in your folder list. In a large number of cases, that is the entire procedure.

There is an important nuance for new Outlook, though, and it trips people up. New Outlook does not use the classic auto-mapping mechanism in the same way, yet shared mailboxes can still appear there automatically. After your admin adds you as a member of a shared mailbox, the recommended move in new Outlook is to close and restart the app: the shared mailbox should then display in your folder pane on its own. If your admin only just added you, it can take a few minutes before the mailbox shows up, so the advice is to wait a little, then close and restart new Outlook again. If it still has not appeared after that, you fall back to adding it manually, which is the next section.

How do you add a shared mailbox in new Outlook or on the web?

If auto-mapping has not delivered the mailbox, or you simply want to add it yourself, new Outlook and Outlook on the web use the same quick method, because they share the same engine. You add the shared mailbox as a separate folder tree that hangs in your folder pane beneath your own account. You will still be signed in as yourself; the shared mailbox just becomes a second set of folders you can open. The whole thing takes well under a minute, assuming your admin has already granted you access.

Here is the step-by-step for new Outlook for Windows and for Outlook on the web. The menus look effectively identical between the two, so this single set of steps covers both.

1. 1

   Open Mail and find your account in the folder pane

   In new Outlook or on the web, select Mail from the navigation pane on the far left so your folder list is showing. In that left-hand folder pane, locate your own account name at the top of your folder tree, the heading above your Inbox, Drafts, and Sent Items.

2. 2

   Right-click your account name

   Right-click (or press and hold) directly on your account name in the folder pane. A short context menu appears with options for managing folders and accounts attached to your mailbox.

3. 3

   Choose "Add shared folder or mailbox"

   From that menu, select "Add shared folder or mailbox." A small dialog opens with a single search box, ready for you to type the mailbox you want to open.

4. 4

   Type the shared mailbox name or address

   In the box, type the name or full email address of the shared mailbox, for example info@contoso.com, and let Outlook resolve it against your organization's directory. Pick the correct match when it appears so you are sure you have the right mailbox.

5. 5

   Add it and watch it appear in the folder pane

   Confirm by selecting Add. The shared mailbox now appears in your folder pane, listed separately below your own account, with its own Inbox and folders. Expand it to read its mail, and select any folder inside it to work there.

That method, adding it as a shared folder, is the one most people want, because it shows the shared mailbox as a clean, separate folder tree alongside your own and it keeps the two clearly distinct. There is a second, slightly different option in new Outlook that is worth knowing about: you can add the shared mailbox as a full additional account rather than as a shared folder. You do that through Settings, in the Accounts section, by adding the shared mailbox like an email account. Adding it as a full account gives it more of its own first-class presence in the app, but for everyday "open the team inbox and answer mail" use, the right-click "Add shared folder or mailbox" route is faster and entirely sufficient.

Once the mailbox is in your folder pane, working in it is intuitive. Click into its Inbox to read incoming mail, open a message, and reply as you normally would, though replying brings up the question of which address the reply goes out from, which we tackle in the send-as section below. You can drag the shared mailbox to reorder where it sits in your folder list, and if you ever want to stop showing it, you right-click the shared mailbox name and choose the option to remove the shared folder, which simply hides it from your view without touching the mailbox itself or your permissions.

How do you add or open a shared mailbox in classic Outlook?

Classic Outlook for Windows is where two things diverge from the modern apps: the menus are the older File-based ones, and auto-mapping is more likely to have already done the job for you. So before you do anything manual in classic Outlook, check whether the mailbox is already there. If your admin granted you Full Access with auto-mapping left on, the shared mailbox most likely appears in your folder list automatically after you restart Outlook. If it is there, you are done; skip the manual steps entirely.

If it has not auto-mapped, or auto-mapping was deliberately turned off for your account, you add the shared mailbox manually through your account settings. This attaches the mailbox as an additional Exchange mailbox under your existing profile. Here is the classic-Outlook procedure.

1. 1

   Open your account settings

   In classic Outlook, go to File, then Info, then Account Settings, and choose Account Settings again from the small dropdown. The Account Settings window opens, listing your email accounts.

2. 2

   Open the More Settings for your account

   On the Email tab, double-click your own Exchange or Microsoft 365 account, the one through which you have permission to the shared mailbox. In the dialog that opens, click "More Settings."

3. 3

   Go to the Advanced tab and add a mailbox

   Switch to the Advanced tab. Under "Open these additional mailboxes," click Add. This is where you attach the shared mailbox so classic Outlook shows it alongside your own.

4. 4

   Enter the shared mailbox name

   Type the name or email address of the shared mailbox and click OK. If more than one match is found, pick the correct one. The mailbox is now listed in the additional-mailboxes box.

5. 5

   Finish and let it sync

   Click OK, then Next, then Finish, and close the windows. The shared mailbox appears as a separate folder tree at the bottom of your folder pane. Give it a moment to download its contents on first open.

There is a related but distinct task that classic Outlook handles in its own way: opening a single folder from another person's mailbox rather than a whole shared mailbox. This is what you want when a colleague has shared just their Calendar, or just their Inbox, with you, rather than you having Full Access to an entire shared account. In classic Outlook you reach it through File, then Open and Export, then "Other User's Folder." In that dialog you type the name of the person who has granted you access, choose which folder type you want to open (Inbox, Calendar, Contacts, and so on), and click OK. The folder opens for you to view, within the limits of whatever that person chose to share.

It is worth being clear about the difference, because the two are easy to confuse. "Other User's Folder" is for peeking into one shared folder belonging to a named individual, and it depends on that individual having shared that specific folder with you. Adding a shared mailbox through account settings, by contrast, attaches an entire mailbox, usually a role-based one like support@, that an administrator has given you Full Access to, and it brings across all of that mailbox's folders. For a genuine team inbox, you want the full-mailbox route. For glancing at one coworker's calendar, "Other User's Folder" is the lighter-weight tool.

What is the difference between send-as and send-on-behalf?

Once you can read a shared mailbox, the next question is how to reply from it, and this is where the two permission types matter. Reading a shared mailbox and sending from it are governed by separate permissions in Exchange, which catches a lot of people off guard. Full Access lets you open the mailbox, read everything in it, and manage its folders, but Full Access by itself does not let you send mail as the shared address. Sending is controlled by one of two additional permissions your admin grants: Send As, or Send on Behalf. They look similar in the compose window but produce very different results for the person receiving your reply.

Send As makes your message appear to come straight from the shared mailbox, with no trace of who actually sent it. If you have Send As on the support@ mailbox and you reply to a customer, they see the message as coming from "Support," full stop. It reads as though the shared mailbox itself sent it, which is usually exactly what a team wants: a single, consistent identity facing the customer, regardless of which team member happened to be at the keyboard. For most help desks, sales lines, and general inboxes, Send As is the permission you want, precisely because it hides the individual and presents one unified face.

Send on Behalf, by contrast, is transparent about who did the sending. A message sent on behalf of a shared mailbox shows up to the recipient as something like "Jordan Lee on behalf of Support," naming both the individual and the shared address. There are situations where that openness is the point, for instance an assistant sending for an executive where the recipient should know a human assistant acted, but for an anonymous team identity it usually is not what you want, because it exposes which staff member replied. The table below lays out how each option behaves so you can match the permission to the impression you want to give.

In practice, sending from the shared mailbox in any version of Outlook comes down to the From field. When you compose a reply or a new message, you make the From field show the shared mailbox address rather than your own. If the From field is not visible, you turn it on (in classic Outlook, the Options tab has a "From" button; in new Outlook and on the web, you can pick the sending identity from the From control at the top of the message). With the From field set to the shared address and the right permission in place, your message goes out as the shared mailbox. The single most common reason mail unexpectedly goes out from your personal address is simply that the From field was left on your own account, so always glance at it before you hit Send.

A practical tip: after you send once from the shared address, Outlook usually remembers it as an option in the From dropdown, so you can switch between your own identity and the shared one per message. This matters for people who work several mailboxes, because it is genuinely easy to fire off a reply from the wrong identity if you are moving quickly. Slow down on the From line until it becomes a habit. If you have only Full Access and neither Send As nor Send on Behalf, you will be able to read and organize the shared mailbox but every attempt to send as it will be rejected, which is the subject of one of the troubleshooting points later on.

How do you save sent mail to the shared mailbox's Sent Items?

Here is a behavior that surprises almost everyone the first time, and quietly causes problems for teams: by default, when you send a message as a shared mailbox or on its behalf, the sent copy is not saved in the shared mailbox's Sent Items folder. It is saved in your own personal Sent Items instead. So a customer gets their reply, the conversation looks handled from the outside, but a teammate opening the shared mailbox sees no record of the reply at all. To them it looks unanswered, which leads to duplicate replies, confusion about what has been dealt with, and a generally incomplete picture in the one place the whole team is supposed to be able to trust.

The fix is a server-side setting that an administrator applies to the shared mailbox, and it is the standard, recommended configuration for any shared mailbox a team works from. Two related options control it: one for copying messages sent as the mailbox, and one for copying messages sent on behalf of it. When both are turned on, every reply, no matter which team member sent it, is saved into the shared mailbox's own Sent Items folder, so everyone can see the full thread of what has gone out. This is not something a regular user can usually flip in their own Outlook settings; it lives with the admin, on the mailbox, which is why it is grouped with the permissions work.

An administrator can enable both behaviors in the Exchange admin center, in the shared mailbox's settings where Sent Items copying is configured, or with a single PowerShell command that sets the two properties at once. The practical command sets "MessageCopyForSentAsEnabled" and "MessageCopyForSendOnBehalfEnabled" to true on the mailbox; once that is done, sent copies from every member start landing in the shared Sent Items. If your team is suffering from "I can never find what we already replied to," this single configuration change is almost always the cure, and it should be considered part of setting a shared mailbox up properly rather than an optional extra.

What does an administrator need to set up first?

Everything in this guide rests on an administrator having done two things on the server: created the shared mailbox, and granted the right people the right permissions to it. If you are that administrator, this section is your checklist; if you are a user, it tells you exactly what to ask for so your request is unambiguous. The work happens in the Microsoft 365 admin center for most modern setups, with the Exchange admin center and PowerShell available for finer control.

Creating the shared mailbox itself is straightforward: in the Microsoft 365 admin center, a shared mailbox is created under the mailbox or shared-mailbox settings, given a name and an address like support@yourdomain.com. A normally-used shared mailbox in Exchange Online does not consume a paid license on its own, which is part of why they are the standard tool for team and role addresses rather than spinning up an extra full account. Once the mailbox exists, the admin assigns the people who should be able to use it, and this is where the distinct permissions come in.

1. 1

   Create or open the shared mailbox

   In the Microsoft 365 admin center, create the shared mailbox (or open an existing one) under the shared mailbox settings, giving it a clear name and address such as support@yourdomain.com. A standard shared mailbox does not require its own license.

2. 2

   Grant Full Access to the members who will open it

   On the shared mailbox, use the option to manage members or permissions and grant Full Access (sometimes shown as "Read and manage") to each person who needs to open and work the mailbox. Full Access is what lets them see and organize its mail.

3. 3

   Grant Send As (or Send on Behalf) for replying

   Separately, grant Send As to anyone who must reply as the shared address (the unified-identity choice), or Send on Behalf if recipients should see who sent it. Full Access alone does not allow sending, so this step is essential for a working team inbox.

4. 4

   Enable copies to the shared Sent Items

   Turn on copying of sent-as and sent-on-behalf mail into the shared mailbox's Sent Items, either in the Exchange admin center or via PowerShell, so every member's replies are visible to the whole team rather than scattered into personal Sent folders.

5. 5

   Tell members to restart Outlook

   Let the granted members know access has been set, and ask them to fully close and reopen Outlook. With auto-mapping on, the mailbox typically appears on its own after a sync; otherwise they add it manually using the steps above. Permission changes can take a little while to propagate.

Two administrative points are worth underlining because they cause the most support tickets. First, Full Access and the sending permissions are genuinely separate, and a user with only Full Access will be able to read the mailbox but will hit an error every time they try to send as it. If a team member reports that they can see the shared mailbox but cannot send from it, the fix is almost always to grant Send As, not to touch Full Access. Second, permission changes are not always instant. After granting access, it can take some minutes for the change to reach a user's Outlook, and auto-mapping in particular relies on a sync cycle, so the standard guidance to affected users is to wait a little and restart Outlook before assuming anything is broken.

Finally, a note on scope and security that matters for any shared inbox: because several people share one identity, a shared mailbox blurs individual accountability by design. That is fine, and even the point, for a customer-facing identity, but it means your only record of who actually sent a given reply, when send-as hides the individual, lives in audit logs rather than in the message itself. For small teams this is usually an acceptable trade. For larger teams that need to know precisely who handled what, it becomes one of the limitations that pushes them toward a purpose-built shared-inbox tool, which we come to after the mobile and troubleshooting sections.

How do you access a shared mailbox on mobile?

Shared mailboxes work on phones too, through the Outlook app for iOS and Android, though with a couple of conditions and a slightly different flow from the desktop. The key requirement is that both your own mailbox and the shared mailbox are in Exchange Online using Microsoft's native sync, which is the normal arrangement for Microsoft 365 organizations. As with every other method here, you also need to have been granted permission to the shared mailbox already; the mobile app cannot conjure access you do not have.

On the Outlook mobile app, you add a shared mailbox much as you would add any account, but through a dedicated option. After signing in with your own work account, you open the account list in the navigation pane, choose to add an account, and then pick the option to add a shared mailbox specifically. If you have more than one account configured in Outlook mobile, the app asks which of your accounts holds the permission to the shared mailbox, so it knows whose access to use. Once you complete that, the shared mailbox shows up in your account list in the app, and you can read and respond to its mail from your phone.

1. 1

   Open the account list in Outlook mobile

   In the Outlook app on iOS or Android, signed in with your primary work account, tap your profile or the menu to open the navigation pane, then tap the option to add an account.

2. 2

   Choose "Add a Shared Mailbox"

   Rather than entering a new personal account, select the dedicated "Add a Shared Mailbox" option. This tells Outlook you want to attach a mailbox you have been granted access to, not set up a fresh account.

3. 3

   Pick the account that holds the permission

   If you have several accounts in Outlook mobile, choose the one that has been granted access to the shared mailbox, so the app uses the right identity to reach it.

4. 4

   Enter the shared mailbox address

   Type the shared mailbox's email address and let Outlook set it up. Because permission is already in place, the app attaches it rather than asking for a separate password.

5. 5

   Find it in your account list

   After setup completes, the shared mailbox appears in your account list in Outlook for iOS or Android. Switch to it to read its mail, and use the From field when composing to send from the shared address.

Mobile access to a shared mailbox is genuinely useful for staffing a team inbox out of hours or on the move, but it is also the area where setups vary the most, and where the requirement for Exchange Online with native sync is least forgiving. If the "Add a Shared Mailbox" option does not behave, the usual culprits are that the shared mailbox is not in Exchange Online in the expected way, that you have not actually been granted access, or that the change has not propagated yet. On a phone as on the desktop, sending from the shared address still depends on having Send As or Send on Behalf, not merely Full Access, so a teammate who can read the shared inbox on mobile but cannot reply from it is hitting the same permission split described earlier.

Why won't my shared mailbox show up, and why can't I send?

Two problems dominate the support queue for shared mailboxes: the mailbox not appearing, and being unable to send from it. The good news is that both have a small set of well-understood causes, and once you know them, most cases resolve in a few minutes. Let us take them in turn, starting with the mailbox simply not showing in your folder pane.

The first thing to confirm is the prerequisite we opened with: that an administrator has actually granted you access. It is genuinely common for a user to be told "you have been added" before the permission was applied, or to expect a mailbox they were never granted. Verify with your admin that Full Access is in place on your account. If it was granted only recently, the second cause is timing: permission changes take a while to reach your Outlook, and auto-mapping relies on a sync cycle. The standard fix is to fully close Outlook, reopen it, and give it a few minutes, then close and reopen once more if needed. A large share of "shared mailbox not showing in Outlook" reports are solved purely by waiting and restarting.

If access is confirmed and time has passed and the mailbox still has not auto-mapped, the third cause is simply that auto-mapping is not doing it for your situation, classic auto-mapping behaves differently across the Outlook versions, and new Outlook in particular may need you to add the mailbox by hand. That is not a failure; it is just the cue to use the manual "Add shared folder or mailbox" steps for your version from earlier in this guide. Adding it manually bypasses the automatic discovery entirely and almost always puts the mailbox in your folder pane straight away, assuming the underlying permission is there.

The second big problem, being unable to send, is nearly always the permission split between Full Access and sending. If you can open and read the shared mailbox but every attempt to send as it bounces back with an error about not having permission, you almost certainly have Full Access without Send As. The remedy is not in your Outlook at all; ask your administrator to grant Send As (for a unified identity) or Send on Behalf (if the recipient should see who replied). This is so common that it is worth treating as the default explanation whenever someone says "I can see it but I can't send from it."

A close cousin of the send problem is mail going out from the wrong address. If your replies from the shared inbox are leaving as your personal address even though you have the right permission, the cause is the From field, not permissions: it was left on your own account. Turn the From field on and explicitly set it to the shared mailbox before sending. And if replies are sending correctly as the shared address but vanishing from the team's view, that is the Sent Items setting from earlier, the copies are landing in your personal Sent folder because the shared-Sent-Items option has not been enabled on the mailbox. Each of these has a precise, separate fix, which is why the table above splits them out rather than lumping them together.

How does AI Emaily handle shared inboxes and delegation across every provider?

Shared mailboxes in Outlook solve a real problem, and for a small team with one role address they are often enough. But the moment a team grows, the cracks this guide has hinted at start to show: several people work one identity with no clear ownership, so two of them answer the same customer; send-as hides who actually replied, so accountability lives only in audit logs; sent mail has to be wrangled into the right folder with a server setting; and none of it stretches beyond the Microsoft world, so a shared Gmail address or an IMAP support box needs an entirely different setup. The Outlook shared mailbox was built for a single mail system and a simpler kind of teamwork than many teams now do.

AI Emaily is an AI-native email client built around the way teams actually share mail today. Instead of bolting several people onto one opaque identity, it gives you a true shared inbox with human-or-agent delegation: you can assign any individual conversation to a specific teammate, so there is clear ownership and two people do not reply to the same message, or hand that conversation to an AI agent that can triage it, draft a reply, sort it, and follow up the way a capable assistant would. You keep humans for the judgment calls and let the agent absorb the repetitive volume, with a full record of who, or what, did each thing.

Crucially, it works across every provider, not just Outlook. The same shared inbox and delegation sit on top of Outlook, Gmail, and other accounts together, so a team running support across more than one mail system manages it all in one place rather than maintaining a separate shared-mailbox configuration per provider. There is no admin-only gate to cross before you can share an inbox and no requirement that everything live in one company's mail system. The agent runs in Manual, Copilot, or Autopilot, always with one-tap undo and an audit trail, so you decide how much it does on its own and can reverse anything in a tap.

AI Emaily starts free at $0, with Pro at $17.99 a month and Team at $22.99 per seat a month, both billed annually, so a small team can try the shared inbox without committing budget up front. If the shared-mailbox dance in this article, the permission splits, the Sent Items setting, the per-provider repetition, is more friction than your team should be spending time on, it is worth seeing how much of it simply disappears when sharing and delegation are built into the client itself. You can start free at app.aiemaily.com/signup.

Putting it all together

Opening and using a shared mailbox in Outlook comes down to a short chain of dependencies, and almost every problem traces back to a link in that chain. First, an administrator grants you access, usually Full Access; nothing works until that is done. Then the mailbox either appears on its own through auto-mapping (most likely in classic Outlook, and after a restart in new Outlook) or you add it by hand, with the right-click "Add shared folder or mailbox" route in new Outlook and on the web, and the Account Settings route in classic Outlook. To reply as the shared address you need a separate sending permission, Send As for a unified identity or Send on Behalf when the recipient should see who acted, and you set the From field to the shared mailbox when you compose.

From there, two finishing touches make a shared mailbox genuinely team-ready: enabling copies of sent mail to the shared Sent Items so everyone can see what has gone out, and knowing the mobile route through the Outlook app's "Add a Shared Mailbox" option for when you are away from your desk. Keep the troubleshooting map in mind, missing mailbox usually means access or sync, can't-send usually means missing Send As, wrong-from means the From field, and missing sent copies means the Sent Items setting, and you will resolve the vast majority of issues yourself in minutes.

And if the whole arrangement starts to feel like more plumbing than your team should be maintaining, especially across more than one email provider, that is the signal to look at a tool where shared inboxes and delegation are native rather than configured. AI Emaily handles team mail with a real shared inbox, human-or-agent delegation, and clear ownership across every provider, starting free at app.aiemaily.com/signup. Either way, you now know exactly how to open, send from, and manage a shared mailbox in whichever Outlook you are using.