Add a Shared Mailbox in Legacy Outlook for Mac

To add a shared mailbox in legacy Outlook for Mac, open Tools > Accounts, select your Exchange account, choose Advanced and then Delegates, and add the mailbox under Open these additional mailboxes. You need permission from your organization first; adding the mailbox in Outlook does not grant access by itself.

What a shared mailbox is and how it works

A shared mailbox is an Exchange mailbox several authorized people can use, commonly for addresses such as support@company.com or invoices@company.com. It has its own inbox, sent items, folders, and often a calendar. Rather than signing in as the mailbox, each person signs in to their own work account and opens the shared mailbox through their granted permissions.

This setup helps a team handle messages in one place. For example, a support team can see whether a customer has already received a reply, while colleagues can use the same calendar to coordinate coverage. It is different from a distribution list: a distribution list forwards or delivers messages to members, but does not normally provide a common inbox and sent-mail history.

These steps apply to Outlook for Mac connected to a Microsoft Exchange or Microsoft 365 work or school account. A personal Outlook.com account, Gmail account, or IMAP mailbox does not gain shared-mailbox functionality just because it is added to Outlook. The organization’s mail system must support the mailbox and grant the appropriate access.

Check permissions before adding it

Ask the mailbox owner or your Microsoft 365 or Exchange administrator to confirm that the mailbox exists and that your account has access. In many organizations, the key permission is Full Access, which lets you open and manage the mailbox and its contents. Your administrator may need to grant it in the Exchange admin center or through the organization’s administration process. Outlook cannot assign this permission on your behalf.

Permission to read and manage a mailbox is separate from permission to send as it. If you need to reply from the team address, request the appropriate sending permission as well:

Full Access lets you open the mailbox, read messages, and work with its folders. It does not, by itself, authorize sending from the shared address.
Send As lets a message appear to recipients as though it came directly from the shared mailbox.
Send on Behalf identifies you as sending on behalf of the mailbox, rather than presenting the message as sent only by the shared address.

Organizations may apply these permissions differently, and permission changes can take time to appear. If an administrator has just added you, allow time for the change to propagate before concluding that the setup has failed.

Add the mailbox in legacy Outlook for Mac

Open Outlook and make sure you are signed in to the Exchange or Microsoft 365 account that was given access.
In the macOS menu bar, choose Tools > Accounts. Select the relevant Exchange account in the accounts list.
Choose Advanced, then open the Delegates tab. Depending on the Outlook build, the section may be labeled Open these additional mailboxes.
Under that section, select the + button. Enter the shared mailbox’s email address, or search for its name if Outlook offers a directory picker.
Select the matching mailbox, confirm the selection, and close the account settings. If Outlook asks you to restart, follow the prompt; otherwise give it a moment to update.

Look in Outlook’s folder list for the mailbox and expand it to see its Inbox and other folders. The location and appearance can vary by Outlook version and sidebar layout. If the mailbox does not appear immediately, wait briefly, then close and reopen Outlook. Avoid adding it as a separate account with a shared password: a shared mailbox is normally opened using your own authorized account, not by signing in as the mailbox.

Confirm access and find the right folders

Once it appears, open the shared Inbox and check whether messages load. You can also expand the mailbox to look for folders such as Sent Items, Drafts, or a team-created folder. A mailbox can be visible even when you have limited rights to some of its folders, so a missing folder or an access-denied message may point to folder-specific permissions rather than a problem with the account itself.

For a useful first check, ask a colleague with access to identify a recent, non-sensitive message or folder that should be there. Do not send a test message to customers simply to confirm setup. If the mailbox is large or Outlook is downloading a substantial amount of data, initial loading can take longer than opening an ordinary folder.

Read, reply, and send from the shared address

You can usually read and organize messages in the shared mailbox once your access is working. When replying, check the sender or From field before sending. Depending on your permissions and Outlook’s configuration, Outlook may use your personal account by default even when you opened the message from the shared Inbox. If the From field is hidden, look for the option to show it in the message window; the exact control can vary between legacy Outlook builds.

When sending a new message, select the shared address in the From field if it is available. If it is not listed, your account may not have Send As or Send on Behalf permission, or Outlook may not yet have refreshed the permission. Do not assume that Full Access includes sending rights. A message sent from your personal address is not equivalent to a message sent as the team, even if the shared mailbox is copied.

Sent-message behavior can also depend on Exchange settings. Some organizations configure messages sent by a delegate to be saved in the shared mailbox’s Sent Items; others may save them in the delegate’s Sent Items or use a different policy. If the team needs a complete shared record, ask the administrator how sent messages are configured rather than relying on the From line alone.

Legacy Outlook versus new Outlook for Mac

The instructions above are for the older, or legacy, Outlook interface. Microsoft has changed Outlook for Mac over time, so the menu path in a newer interface may not match the Delegates tab described here. In newer Outlook versions, shared mailboxes may be opened through a different account or mailbox-sharing control. The exact options depend on the Outlook release and the organization’s Exchange setup.

If you cannot find Tools > Accounts or the Delegates tab, first check whether you are using new Outlook rather than legacy Outlook. Some versions provide a switch to return to legacy Outlook, but its availability depends on the version and organization. Do not change modes just to troubleshoot if your organization manages Outlook or has disabled that option. Ask your IT team which interface and procedure it supports.

Also distinguish adding a mailbox manually from automatic mailbox discovery. Some Exchange configurations can make a mailbox appear automatically after permissions are assigned; others require the manual steps above. If it already appears in the folder list, do not add a second copy without checking with your administrator, since duplicate entries can make navigation confusing.

Common problems and practical fixes

The mailbox is not found in the picker: Check the spelling and use the full email address. Confirm that the mailbox is an Exchange shared mailbox in your organization, not just a group address or an external mailbox.
The mailbox is added but will not open: Ask the administrator to verify Full Access for the exact account you use in Outlook. If access was granted moments ago, wait for it to propagate, then restart Outlook and check again.
You can read mail but cannot send from the address: Request Send As or Send on Behalf permission, depending on the intended sender display. Full Access alone is not enough.
Some folders are missing or show an error: The mailbox may have folder-level permissions, or a particular folder may have different access settings. Ask the owner or administrator to check that folder’s permissions.
Messages appear slowly or the mailbox looks incomplete: Allow synchronization to finish, especially for a large mailbox or a first-time setup. Check your network connection and reopen Outlook. If the problem persists, record the mailbox address and exact error for IT.
You see the mailbox twice: It may have been discovered automatically as well as added manually. Avoid deleting data or removing account permissions; ask your administrator which entry to keep, then remove only the redundant mailbox entry if appropriate.

When reporting a problem, include your Outlook version, macOS version, the Exchange account you are signed in with, the mailbox address, and the exact error text. Do not include passwords or screenshots containing private messages. Those details help IT distinguish a client-interface issue from missing permissions or an Exchange service problem.

Privacy and good team practices

Access to a shared mailbox can expose messages intended for a whole team, so use it only for an approved work purpose. A shared mailbox is not a secure way to pass around a password, and team members should not sign in with a common account unless an administrator has explicitly designed a different supported arrangement. Individual accounts make access easier to audit and revoke when someone changes roles.

Agree on simple handling practices with the team: who owns a new request, whether staff mark messages as read, how to signal that a message is being handled, and where completed items should go. Without a process, two people may reply to the same customer or assume someone else has responded. Follow your organization’s retention, confidentiality, and records policies when moving or deleting messages.

When to use another option

If the address only needs to distribute announcements to individuals, a distribution list may be more suitable than a shared mailbox. If a group needs to manage conversations as assigned work, a Microsoft 365 group or a dedicated service-management tool may provide better assignment and tracking features, depending on what the organization licenses and supports. A shared mailbox is most appropriate when people need a common email address and shared access to the same mailbox folders.

If you are using Outlook on the web or a different Outlook version, the mailbox can often be opened there using that client’s own shared-mailbox controls. That can be a useful comparison when the permissions are confirmed but the legacy Mac interface is unavailable. It does not remove the need for authorization, and the exact web steps depend on your organization’s setup.

Frequently Asked Questions

Can I add a shared mailbox in legacy Outlook for Mac without admin help?
You can add it yourself if an administrator or mailbox owner has already granted the required access and your organization allows manual setup. Outlook cannot grant you mailbox permissions.

Why can I open the mailbox but not send email from it?
Opening it generally requires Full Access, while sending requires Send As or Send on Behalf permission. Ask your administrator which sending permission matches your team’s needs.

Should I add the shared mailbox as a new Outlook account?
Usually not. Add it as an additional mailbox under your authorized Exchange account. Do not use a shared password unless your organization specifically instructs you to follow a supported alternative.

How long does it take for a shared mailbox to appear?
It may appear after a short delay, but permission changes can take longer to propagate. Wait, restart Outlook, and confirm the permission with IT if it still does not show up.

What if I cannot find the Delegates tab?
You may be using new Outlook, a different Outlook build, or an account type that does not support this setup. Check which Outlook interface you have and ask IT for the matching procedure rather than guessing at a menu path.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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