Hey all,
We successfully completed our migration of all user mailboxes from our on-premise Exchange 2010 server to Office 365, and would now like to decommission the on-premise Exchange 2010 server. We have a separate server that we are leaving on-premises for management, which only has the EMC and no mailbox role. But the old mailbox server should be decommissioned now. It has been turned off for weeks with no impact. We have removed the hybrid configuration. MX records and autodiscover are all moved. DirSync is in place and working.
When attempting to uninstall Exchange 2010 from the old mailbox server, we are getting the error "This mailbox database contains one or more mailboxes, mailbox plans, archive mailboxes, or arbitration mailboxes." and cannot continue. The error suggests either moving the arbitration mailbox or disabling the mailbox if this is the last server in the organization. Since we don't have any other mailbox servers, there is nowhere to move it. And disabling the mailbox makes me nervous because though this is the last on-premise server, I don't want this to affect our cloud services by assuming we are decommissioning the organization. What do we do with the system and arbitration mailboxes?
We have read the article here but it does not fulfill our specific need: http://blogs.technet.com/b/exchange/archive/2012/12/05/decommissioning-your-exchange-2010-servers-in-a-hybrid-deployment.aspx
Also, and I'm not sure if this is a separate topic, how can we make sure that removing this on-premise mailbox server will not remove mail attributes from our user objects?
Thanks!