For my 284, I completely wiped out my rig and installed everything from scratch. Most things have been going along smoothly. Today, I discovered something which was a shock to me. I did not raise the domain functional level to Server 2003 when I installed AD on my 1st DC. I went on to install Exchange 2003 and left it running in the mixed mode. Now obviously, I cannot get the full functionality of Exchange. So the question is, can I raise the domain's functional level and change Exchange's working mode to native without problems? Would Exchange or AD complain loudly and crap itself? I know I seem like a bum posting this.