So we have done an Exchange upgrade from 2007 to 2013 and have got to the stage of test shutting down the old server. Everything seems OK except I can't add a profile with Autodiscover if that user is not logged in to the test machine. Put it another way, I log in as me to a machine I have never logged in on, fire up Outlook (2010) and it Autodiscovers my mailbox etc no problem. But if I try to add a 2nd users profile through control panel, Autodiscover complains that "Exchange is unavailable and Outlook must be online to complete this action." Then if I go into More Settings and manually add the server through HTTP it will connect to the 2nd users mailbox with no issue. This will be a major issue if they upgrade to Office 2013 as there's no option to manually input your server, you can ONLY use Autodiscover in that case.