Symptoms
In Microsoft Outlook 2016 for Mac and Outlook for Mac 2011, you cannot connect to legacy public folders. These are public folders stored on a version of Exchange that is earlier than the version on which your current mailbox is stored.
For example, if your mailbox is homed on Microsoft Exchange Server 2013, you will be unable to connect to public folders stored on Microsoft Exchange Server 2010 or Microsoft Exchange Server 2007.
Cause
This is a limitation of the EWS protocol that Outlook for Mac uses to connect to Exchange Server.
Resolution
To resolve this issue in Outlook 2016 for Mac with Exchange Server 2016 or Exchange Server 2013, install the following updates:
On the Outlook 2016 for Mac client: Install the April 12, 2016, update for Outlook 2016 for Mac (version 15.21.1), or a later update. For information about this update, click the following article number to view the article in the Microsoft Knowledge Base:
3142577 MS16-042: Description of the security update for Office 2016 for Mac: April 12, 2016
On the Exchange Server: Install Cumulative Update 2 for Exchange 2016, or Cumulative Update 13 for Exchange Server 2013, or a later cumulative update. For information about these updates, click the following article number to view the article in the Microsoft Knowledge Base:
Cumulative Update 2 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.
Cumulative Update 13 for Exchange Server 2013 or a later cumulative update for Exchange Server 2013.
The following table summarizes the access state for Outlook 2016 for Mac (post the April 2016 update) access to public folders, and the minimum exchange CU required to enable access:
Public folder deployed on: |
User mailbox on E2010 SP3+ |
User mailbox on E2013 |
User mailbox on E2016 |
User mailbox on Office 365 Exchange Online |
Exchange Server 2010 SP3+ |
Yes |
Yes |
Yes |
Not supported |
Exchange Server 2013 CU13+ |
Not supported |
Yes |
Yes |
Yes |
Exchange Server 2016 CU2+ |
Not supported |
Yes |
Yes |
Yes |
Office 365 Exchange Online tenant |
Not supported |
Yes |
Yes |
Yes |
For more information, view the following blog post: Outlook for Mac and public folder access
Workaround
If you can't install the updates that are mentioned in the "Resolution" section to fix this issue, to work around this issue, migrate the legacy public folders to the current version of Exchange. Or, move the mailbox back to the earlier version of Exchange on which your public folders are currently stored.