It has been a while since I did a transition for Exchange server 2010, and last days I did one…
Today I was doing the final part of it which is decommissioning the old server, I did it but I had to do some extra work to finish the job…
I had moved all the users mailboxes to the new server, and the database seems empty, but in fact, it was not, because there were some system mailboxes called Arbitration mailboxes
So when trying to uninstall the server, I got the error about existing mailboxes still on the database of the server I want to remove!
All I had to do is move these mailboxes to the new server and I was done (NEVER REMOVE THESE MAILBOXES UNLESS YOU ARE REMOVING THE LAST SERVER IN THE ORGANIZATION)
- The first step is to list all the arbitration mailboxes