Opening a Shared Calendar in Outlook for Mac

How you open a shared calendar in Microsoft Outlook for Mac depends on whether the person whose calendar you're opening has shared (not to mention, even wants to share) their primary calendar with you or if they just want to share a secondary calendar. 

If the Primary Calendar Was Shared
If they've shared their primary calendar with you, then it's possible to use the Open Shared Calendar button in Outlook's ribbon. If a user shares their primary calendar with you, they can also share any secondary calendars and they'll be automatically available to you. To open a primary shared calendar:
  1. Simply click the Open Shared Calendar button in Outlook's ribbon
  2. A modal window opens
  3. Type in the user's full email address
  4. Select their username from the list of users that are displayed
  5. Click the Open button 
Once you've done this, their calendar -- and any secondary calendars that they've shared with you -- will be displayed and available to be viewed when accessing the Calendar in Outlook.

If the Primary Calendar Was Not Shared
If a user doesn't share their primary calendar with you, and only wants to share a secondary calendar, it's not possible to use the Open Shared Calendar button. This is NOT a SmarterMail limitation, but a limitation of the Outlook for Mac client. Therefore, instead of using the Open Shared Calendar button, you'll need to add that user as a Delegate to your account. That way, you can open any secondary calendar they share with you. (However, you can NOT access their primary calendar.) To add a Delegate:
  1. With Outlook for Mac open, click on Tools from the Status bar
  2. Select Account from the dropdown and your Accounts modal will open
  3. Select your account (if more than one is listed) and click on the Advanced button
  4. Click on the Delegates tab
  5. Click the Plus (+) sign under "Open these additional mailboxes:" 
  6. The Choose a Person modal opens -- Type the user's full email address
  7. Select their username from the list of uses that are displayed
  8. Click the Add button
Once you've done this, their secondary calendar(s) -- and ONLY their secondary calendar(s) -- will be displayed and available to be viewed when accessing the Calendar in Outlook.