Exchange 2013 Decommission: Unable to uninstall exchange 2013 because still holding older exchange records.

If you already migrate all exchange 2013 arbitration mailboxes to exchange 2016 but you found there are still the older exchange arbitration mailboxes in exchange 2013 which is useless, and these mailboxes shows as disable object in the Active Directory (Windows Server 2016). However, these has prevent you from disable or remove the mailboxes from the exchange 2013 via exchange powershell and prevent you to proceed to perform the uninstall of exchange 2013, because its status is still show as “Active”.

Here are the steps on how to resolve it;

  1. Make sure anti-virus is disable
  2. Remove these old arbitration mailboxes/Discovery mailboxes/Monitoring Mailboxes (please refer the reference for the sample  list) object from Active directory
  3. Before removing the object, take note to check the object’s “homeMDB” attribute with the value of the Exchange 2013 Mailbox Database name(You can get it by typing this powershell command in the exchange powershell “Get-MailboxDatabase” ). (If you remove the wrong one will be troublesome to recover)
  4. Go to exchange 2013 > Open control panel > Programs and features > Select the Microsoft Exchange cumulative update > Right click it and select uninstall > refresh control panel page make sure it is uninstall
  5. After completion uninstall, restart the server > disjoin the server from domain > remove the server object from Active Directory



If you complete above step but still unable to uninstall via GUI because an error pop-up saying “incomplete installation…” than please run the cmd as administrator and use the cmd command to uninstall. (Please refer to reference)