Add a Shared Mailbox in Outlook 365: Step-by-Step Guide

To add a shared mailbox in Outlook 365, first make sure your Microsoft 365 administrator has granted you access, then add the mailbox using the steps for classic Outlook, new Outlook, Outlook on the web, or Mac. A shared mailbox lets several people read and manage the same email address; it does not automatically give everyone permission to send from that address.

The menu names can differ between Outlook versions, so identify which app you are using before you begin. The instructions below cover the common Microsoft 365 versions and explain how to check that the mailbox is connected.

What You’ll Need

Permission to access the mailbox. Ask your Microsoft 365 or Exchange administrator to grant you Full Access. This permission lets you open and manage its messages and folders. It is separate from Send As and Send on Behalf permissions, which control how you send messages.
The shared mailbox address. Have the complete email address, such as support@example.com. Confirm with your administrator that it is a shared mailbox and that you have access to the correct one.
A signed-in Outlook account in the same organization. Use the work or school account to which the administrator assigned access. Access may not work if you are signed in to a different organization or personal Microsoft account.
A little time for permissions to take effect. New access can take a while to appear. If you were just added, allow some time, then close and reopen Outlook before troubleshooting.

Step-by-Step

Confirm your access before changing Outlook settings. Contact the mailbox owner or administrator and ask them to verify that your work account has Full Access to the shared mailbox. If you need to send email as the shared address, also request Send As or Send on Behalf permission, as appropriate. These are separate permissions: being able to open the inbox does not necessarily mean you can send from it. Tell the administrator the exact email address you use to sign in, especially if you have more than one work account.
Identify your Outlook version. In Windows, new Outlook has a simplified interface and a Settings gear; classic Outlook has the File tab on the ribbon. Outlook on the web runs in a browser at your organization’s Microsoft 365 Outlook site. On a Mac, use Outlook for Mac. Choose the matching instructions below; do not follow the classic Outlook account-settings path in new Outlook, because its menus are different.
Add it in new Outlook for Windows. Open Outlook and sign in with the account that was granted access. Select Settings (the gear), then go to Accounts > Shared with me. Select Add a shared folder or mailbox, enter the shared mailbox’s email address, and choose it when Outlook finds it. Confirm the addition. The mailbox should appear in the folder pane, usually under a Shared with me section. Expand it to see the Inbox and other folders. If the setting is not available, update Outlook and check that you are using the new Outlook app rather than classic Outlook.
Add it manually in classic Outlook for Windows if it has not appeared automatically. Outlook may add a mailbox on its own after Full Access is granted; first close and reopen Outlook and look in the folder pane. If it is still missing, select File > Account Settings > Account Settings. On the Email tab, select your Microsoft 365 or Exchange account and choose Change. Select More Settings, open the Advanced tab, and choose Add under Open these additional mailboxes. Type the shared mailbox address, select OK, then choose Apply and OK to close the settings. Finish the prompts and restart Outlook. Menu availability can vary with account configuration; if Change or the Advanced tab is unavailable, ask your administrator whether the mailbox should be added automatically or use Outlook on the web as a check.
Add it in Outlook on the web. Sign in to Outlook on the web with your work account. In the folder pane, right-click Folders (or the folder pane heading, depending on the layout), choose Add shared folder or mailbox, enter the mailbox address, and select the matching result. The mailbox should appear in the folder list. If you only need to open it temporarily, select your profile picture, choose Open another mailbox, enter the address, and open the result. That opens the mailbox in a separate browser view; adding it to the folder pane is more convenient for regular use.
Add it in Outlook for Mac. In Outlook, open Outlook > Settings > Accounts, select your Microsoft 365 account, then open Delegation and Sharing. Under Shared With Me, select the plus sign, enter the shared mailbox address, and select the mailbox to add it. Close Settings and check the folder pane. The labels may vary slightly between Outlook for Mac releases. If you do not see the Shared With Me option, update Outlook and verify that your account has Full Access.
Check that the mailbox is usable. Expand the mailbox in the folder pane and open its Inbox. Open a message and confirm that the sender, recipients, and folders belong to the shared mailbox, not your personal account. If you have permission, try creating a draft addressed to yourself, then discard it. This checks that the mailbox is available without sending an unintended message.
Choose the shared address when composing, if you have permission to send. Start a new message. In classic Outlook, select From; if the field is hidden, look for it in the message window’s Options controls. Choose the shared address or use Other Email Address to enter it. In new Outlook or Outlook on the web, start a message, select Options > Show From if From is not visible, then select the From address and choose or enter the shared mailbox. In Outlook for Mac, show the From field in the message window and choose the shared address. Send a test only if appropriate. If Outlook rejects the address, ask the administrator to check your Send As or Send on Behalf permission.

Common Mistakes

Assuming access to the inbox includes permission to send. Full Access and sending permissions are distinct. You can be able to read and organize messages but still be blocked from sending as the mailbox.
Adding the wrong address or account. Similar names can refer to different mailboxes, and access is assigned to a particular work account. Check both the full mailbox address and the account shown in Outlook before repeating setup.
Adding it repeatedly. A mailbox may already have been added automatically. Look through the folder pane and expand existing sections before using Add again. Duplicate entries can make it unclear which mailbox you are working in.
Expecting the shared Inbox to merge with your personal Inbox. A shared mailbox appears as its own mailbox and folder tree. Its messages do not normally become part of your personal Inbox.
Changing unrelated account settings. Do not remove your Microsoft 365 account or create a new Outlook profile as a first step. Those actions can affect other mail and calendars and rarely solve a missing permission.
Forgetting which From address is selected. Before sending, check the From line and recipient list. Outlook may remember a previously selected sender, and a message from your personal account could go to the wrong recipients.

Tips

Use the shared mailbox’s own folders. When you reply to a message, open it from the shared mailbox and check that the From field shows the shared address. This makes it easier for colleagues to follow the conversation.
Agree on a team routine. If several people handle the same messages, decide who will reply, how to mark messages that are being handled, and whether categories or folders will be used. Otherwise, two people may answer the same customer or everyone may assume someone else has replied.
Check the Sent Items location. Depending on your organization’s Exchange settings, a message sent as the shared mailbox may be saved in your personal Sent Items, the shared mailbox’s Sent Items, or both. If colleagues need to see every reply, ask the administrator whether copies of sent messages should be saved in the shared mailbox.
Keep the mailbox address handy. If it does not appear in a From list, enter the full address only after confirming that the correct sending permission has been assigned. A saved address is not proof that Outlook will authorize sending.
Use Outlook on the web to narrow down the cause. If the mailbox works in the browser but not in the desktop app, access is probably in place and the issue may be local to the desktop app’s folder list or cached connection. If it fails in both, permission or account selection is a more likely place to start.

Troubleshooting

The mailbox does not appear. First verify that you signed in with the account that received Full Access. Close and reopen Outlook, then wait and check again if permission was recently granted. In new Outlook, try the Shared with me setting; in classic Outlook, check whether it was auto-added before adding it manually. If your organization assigned access through a group, automatic mapping may not happen in the same way as when access is assigned directly. Ask the administrator to confirm the permission and advise whether manual addition is supported.

The mailbox appears, but folders are missing or will not load. Expand the mailbox in the folder pane and give Outlook a moment to synchronize. Restart the app and check your internet connection. Try opening the same mailbox in Outlook on the web. If the browser works but the desktop app remains out of date, install available Office updates and restart. Avoid deleting messages or folders as a test, because changes in a shared mailbox may be visible to everyone.

You can read messages but cannot send from the shared address. Confirm that the From field is visible and that the shared address is selected. If Outlook displays an access or permission error, ask the administrator to grant the required Send As or Send on Behalf permission. After permission is changed, allow time for it to apply, restart Outlook, and try again. Do not repeatedly send test messages to external recipients.

Outlook says the mailbox cannot be found. Check for spelling errors and confirm the full address with the mailbox owner. Ask the administrator whether the mailbox exists, is active, and has been shared with your account. If the mailbox was recently created or renamed, the address or directory entry may not yet be updated everywhere.

You see duplicate mailboxes or the wrong one. Compare the displayed addresses and check whether Outlook added one automatically as well as through a manual setup. In new Outlook or the web, use the mailbox’s context menu to remove an added shared folder if that option is available. In classic Outlook, a manually added mailbox can generally be removed from the Advanced tab where it was added. For an automatically mapped mailbox, ask the administrator to remove or adjust access rather than deleting your work account. Restart Outlook after a change.

Frequently Asked Questions

Why is a shared mailbox not showing in Outlook 365?
Most often, Full Access has not been granted to the account you are using, Outlook has not refreshed since access was granted, or the mailbox has not been added to that Outlook version. Confirm the account and permission first, then restart Outlook or add the mailbox using the matching instructions above.

Can I add a shared mailbox without an administrator?
You can add it yourself only if the mailbox already exists and your account has been granted access. If you do not have Full Access, Outlook cannot create access for you. Ask your Microsoft 365 administrator or the mailbox owner to arrange the required permissions.

Does adding the mailbox give me permission to send email from it?
No. Full Access lets you open and manage the mailbox. Send As and Send on Behalf are separate permissions. Ask which sending option your organization wants you to use, then check the From line before sending.

Can I add the same shared mailbox on more than one device?
Yes, if the same work account has permission and the Outlook app supports shared mailboxes. Add it separately on each device or use automatic mapping where available. You may need to wait for changes to synchronize, and the steps can differ between Windows, Mac, and the web.

How do I remove a shared mailbox from Outlook?
For a mailbox you added in new Outlook or Outlook on the web, open its context menu and select the available remove option. For a mailbox you manually added in classic Outlook, remove it through the same Advanced account settings where it was added. If it keeps returning because it was automatically mapped, ask the administrator to change your Full Access permission.

Will other people see the changes I make?
Usually, yes. Messages you move, mark, or delete in a shared mailbox affect the mailbox shared with the team. Sent-message visibility depends on your organization’s settings. Treat the mailbox as a shared workspace and follow your team’s process for handling messages.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

More in How-to basics

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

Spotted an error in this guide? Let us know.