Access Another Mailbox in Microsoft 365

Access Another Mailbox in Microsoft 365

Access Another Mailbox in Microsoft 365

Overview

If you have been given permission to a shared mailbox, a coworker's inbox, or a department mailbox, this guide shows you how to open it inside Outlook so you can read and manage its mail alongside your own.

Before You Begin

  • Permission to access the other mailbox. Your administrator or the mailbox owner must grant this — you cannot grant it to yourself.
  • Outlook on the web, Outlook for Windows, or the Outlook mobile app.
  • The email address of the mailbox you want to open.

Steps

Outlook on the Web (Recommended)

  1. Open Outlook in your browser at outlook.office.com.
  2. In the left sidebar, right-click Folders (or your name at the top of the folder list).
  3. Click Add shared folder or mailbox.
  4. Type the email address of the mailbox, then click Add.
  5. The mailbox appears in your sidebar. Click it to expand and read mail.

New Outlook for Windows

  1. Open New Outlook.
  2. Right-click your name or Folders in the sidebar.
  3. Click Add shared folder or mailbox.
  4. Type the email address and click Add.

Classic Outlook for Windows

  1. Click File → Account Settings → Account Settings.
  2. Pick your account and click Change.
  3. Click More Settings → Advanced tab.
  4. Click Add and type the mailbox name.
  5. Click OK, then Next, then Finish.
  6. The mailbox appears below your inbox in the folder list.

Outlook Mobile

  1. Open the Outlook app and tap your profile picture in the top left.
  2. Tap the inbox icon with a plus sign.
  3. Tap Add a Shared Mailbox.
  4. Sign in with your own credentials if prompted.
  5. Pick the mailbox from the list.

Troubleshooting

  • If the mailbox does not appear after adding: wait 10–15 minutes for permissions to sync, then close and reopen Outlook.
  • If you get an "access denied" error: confirm with your administrator that permissions have been granted. Permission can take up to an hour to take effect.
  • If you can read but not send: see the article on Send Email From a Shared Mailbox — sending requires a separate permission.
  • If mail looks duplicated: classic Outlook sometimes downloads shared mail twice during initial sync. Wait for the sync to finish before deleting anything.

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