Symptoms
When you try to move a public folder mailbox, the attempt fails, and the following error message is recorded in the move request report:
StatusDetail: StalledDueToMRS_Quarantined
Message: Request was quarantined because of following error: Object of type "Microsoft.Exchange.Data.Storage.PublicFolderSession" cannot be converted to object of type "Microsoft.Exchange.Data.Storage.MailboxSession".
Resolution
To fix this issue, install Cumulative Update 13 or a later cumulative update for Exchange Server 2019.
