Adding a shared mailbox to Outlook for Mac - Instructions for Connect (on-prem) Shared Mailboxes


Outlook for Mac users are not able to use the "new" Outlook if they have a shared account in Outlook. For more information, please see this article

To add a shared mailbox it is necessary to have both of the following:
          (i) a security group that grants “Send-as” and full access permissions to all folders of the shared mailbox
          (ii) your username must be a member of the mailbox security group as your account requires permission to the shared mailbox for authentication using your own credentials.

Contact IST Service Desk or your computer support rep if you need help to meet the above requirements.

Instructions for Connect (on-prem) Shared Mailboxes

  1. Open Outlook for Mac.

  2. Click Tools on the menu bar, and then click Accounts… from the drop-down list.

  3. Click on the plus sign button near the lower-left corner, and then click New Account… from the pop-up menu.

  4. Type in the 8-character username of the shared mailbox (i.e. and then click the Continue button.


  5. Click on Exchange (top row at right) at the “Choose the provider for…” prompt.

  6. Enter the following in the “Set Up Your Email” window (Username is your 8-character username, i.e. j25rober) and then Click the Add Account button

    1. Leave “Method: Username and Password” as it appears

    2. Leave “Email Address” as it appears.

    3. DOMAIN\username or mail: enter your (e.g. Note the DOMAIN prefix isn't required. 

    4. Password: your UWaterloo password

    5. Server (optional):

  7. You will see a message prompt that your shared mailbox has been added. Click the “Done” button near the bottom of the window to return to the Accounts window.

  8. Close the Accounts Window.

  9. The next time you click on the “New Email” button, you will be able to choose which account you want to use to send a message by clicking the “From:” drop-down list.

  10. Try sending a test message from the shared mailbox to ensure the account is working properly.


If you see the Outlook was redirected to the server autodiscover... dialog box:

  • Click on the Always use my response for this server check box.

  • Click on the Allow button.