This post is focused on those of you who have decided to deploy Exchange in a resource forest. You’re in for tears. While the resource forest is technically a supported deployment method for Exchange, I’m going to point out what can go wrong in your Exchange world that will keep your admins up at night. Let’s start with the definition of a resource forest, just in case you’re not sure. The resource forest approach means that you have one Active Directoryforest where your user accounts live and another Active Directory forest where your application (Exchange, in this case) lives.