Up to the point when I tried to uninstall Exchange 2003, my upgrade went as smooth as silk--surprisingly so. But I couldn't deinstall 2003 and the reason, it turns out, was that I forgot to run the step that makes AD ready for 2007. In spite of my SNAFU, everything seems to be running properly but I need to decommission the 2003 box so I'm wondering how to recover from this. Can anyone point me in the right direction?

Hello Peter, Exchange setup should have taken care about preparation of your AD if you didn't do it separately while installing first Exchange server into environment because that is the first task and prerequisite for Exchange. Follow below step-by-step method to remove your Exchange server if it is last 2003 server in your environment. How to Remove the Last Legacy Exchange Server from an Organization http://technet.microsoft.com/en-us/library/bb288905(EXCHG.80).aspx OR here is a nice set of articles for it. http://www.msexchange.org/articles_tutorials/exchange-server-2007/migration-deployment/removing-last-exchange-2003-server-exchange-2007-part1.html http://www.msexchange.org/articles-tutorials/exchange-server-2007/migration-deployment/removing-last-exchange-2003-server-exchange-2007-part2.html http://www.msexchange.org/articles-tutorials/exchange-server-2007/migration-deployment/removing-last-exchange-2003-server-exchange-2007-part3.html http://www.msexchange.org/articles-tutorials/exchange-server-2007/migration-deployment/removing-last-exchange-2003-server-exchange-2007-part4.html