“Default VoiceMessageOriginator contact already exists”

Another error from the Exchange 2007 beta setup parade: after you remove a server, when you reinstall, you may get an error that says that “Default VoiceMessageOriginator contact already exists”. The trick to fix this is to launch ADU&C, turn on advanced mode, and open the Microsoft Exchange System Objects container. In that container, you’ll see an object called Exchange UM<GUID>. This object is used to represent the system as the sender of UM messages. You’ll need to remove it. (Microsoft is planning to change the way the sender object is created in future builds, so this is a beta-2-only bug.)