Scenario:
During the Public folder migration in Exchange and Office 365 hybrid environment, you will receive the error 'HoldForMigration' when you try to create Public folder mailboxes on Exchange online (Office 365)
The following error occurs when the Public folder is configured as 'Remote' during the Exchange server hybrid deployment.
Error: An existing Public Folder deployment has been detected. To migrate existing Public Folder data, create new Public Folder mailbox using -HoldForMigration switch