Outlook can't access public folders hosted on legacy Exchange servers

Original KB number:  3177600


Consider the following scenario:

  • In your Microsoft Exchange environment, Exchange Server 2010 coexists with either Exchange Server 2013 or Exchange Server 2016.
  • Public folders are hosted on the Exchange 2010 servers.
  • Access to the legacy public folders has been configured according to the guidelines in Configure legacy public folders where user mailboxes are on Exchange 2013 servers.
  • There are multiple Exchange 2010 public folder databases.

In this scenario, users who have an Exchange 2013-based or Exchange 2016-based mailbox can't access public folders by using Microsoft Outlook.


This issue occurs if the mailbox database that hosts the user's mailbox is configured for a public folder database that differs from the public folder discovery mailbox database.


To resolve this issue, configure the user's mailbox database to use the same public folder database as the discovery mailbox:

  1. Assign a public folder discovery mailbox to the user's mailbox by using the Set-Mailbox cmdlet, as follows:

    Set-Mailbox <User> -DefaultPublicFolderMailbox <ProxyMailbox>
  2. Assign the public folder database for the user's mailbox database by using the Set-MailboxDatabase cmdlet, as follows:

    Set-MailboxDatabase (Get-Mailbox <User>).Database -PublicFolderDatabase (Get-MailboxDatabase (Get-Mailbox <ProxyMailbox>).Database).PublicFolderDatabase
  3. Run the following cmdlet to restart the Microsoft Exchange Rpc Client Access service on the server that's running Exchange Server that hosts the public folders:

    Restart-Service MSExchangeRPC