I have a site that is on domainOLD. The rest of my organization is on domainNEW. There is a valid trust between the two. We need to move them off domainOLD to domainNEW. We are deploying a DC at their site under domainNEW. We will be moving all of those
PCs off domainOLD and into domainNEW. My problem is that many of the domainOLD users have linked mailboxes. This means they already have an account on both domains, and their mailbox in Exchange 2013 is linked back to domainOLD with domainNEW as an additional
SMTP. Some of the users also have both a linked mailbox at domainOLD and a user mailbox at domainNEW.
Soon, the domainOLD domain controller will be demoted. Then there will be no domain for these accounts to be linked to at all. I don't know what to do to convert them over before hand.