Error when creating a public folder mailbox in Exchange Server: An existing Public Folder deployment has been detected

Original KB number:  3004062

Symptoms

When you try to create a public folder mailbox in Microsoft Exchange Server, you receive the following error message:

An existing Public Folder deployment has been detected. To migrate existing Public Folder data, create new Public
Folder mailbox using -HoldForMigration switch.

Cause

This problem occurs when the Exchange organization coexists with an earlier version of Exchange Server, and one or more public folder databases from the earlier version of Exchange still exist.

Resolution

To resolve this issue, use one of the following methods.

Method 1: Create the mailbox by using the -HoldForMigration switch

This option lets an administrator create a public folder mailbox in order to begin a migration from the existing public folders:

1. Open the Exchange Management Shell.

2. Run the following cmdlet to create the public folder mailbox:

   New-Mailbox "Public Folder Mailbox" -PublicFolder -HoldForMigration
   

Method 2: Remove all public folder databases from earlier versions of Exchange Server

1. Remove existing public folder databases. To do this, see Remove Public Folder Databases.
2. Create the public folder mailbox by using either the Exchange Admin Center (EAC) or the Exchange Management Shell (EMS). To do this, see Create a public folder mailbox.