Hi Everyone! In my test enviroment, I have some server below: - DC2008: Domain Controller Windows Server 2008 R2 - Edge 2007: With Edge Transport Role Exchange 2007 SP3 - EX2013: CAS/Mailbox roles exchange 2013 - EX2013-1: Mailbox roles Exchange 2013 (will plan set up but failed) All server are running on Windows server 2008 R2 and are member server with domain ABC.LOCAL Currently, the EX2013 is working fine, emails can send/receive via Edge server Now, I want to test DAG (Database Availability Groups) on Exchange 2013, so I have set up new EX2013-1 server with Mailbox role. Then will test DAG between EX2013 and EX2013-1. But when I install the error message occur as below. [06/05/2012 21:52:19.0740] [1] [REQUIRED] The Mailbox server role is already installed on this computer. [06/05/2012 21:52:19.0740] [1] Help URL: http://technet.microsoft.com/library(EXCHG.150)/ms.exch.setupreadiness.MailboxRoleAlreadyExists.aspx But this is a new server and doesn't have any exchange server before. And on AD there is only one EXchange 2013 installed is EX2013 server name. Is there anyone get the same error like this? Please help me in this case! Appreciated thank all!

Have you tested with a completly different name? not the -1? James.

Hi James! Does it mean I need disjoin EX2013-1 server out of domain and join domain again with another name? I checked on AD and found that there is Microsoft Exchange System Object with Mailbox file inside. Does I need delete this file or this file generated from EX2013 server (the first Exchange server)?

Have you tested with a completly different name? not the -1? James.

Hi James! Does it mean I need disjoin EX2013-1 server out of domain and join domain again with another name? I checked on AD and found that there is Microsoft Exchange System Object with Mailbox file inside. Does I need delete this file or this file generated from EX2013 server (the first Exchange server)?

Hi You had better join domain again with another name. First Exchange server won't generate object on other server.Terence Yu TechNet Community Support