Hi, I have exchange 2003 enterprise with SP1 hosting 4000 Mailbox in a production network. Now I want to buy one more server and do a two node cluster. I read on Microsoft web site that if I have already installed exchange 2003 in non-cluster mode then to make it cluster I have to re-install exchange 2003. I just thought of asking experts. Can some one please let me know the steps & risks involved. Regards Praveen R --------------------------------- Yahoo! for Good Click here to donate to the Hurricane Katrina relief effort.