Dear All, I am running NT4.0 and MS exchange server 5.5. I am going to install advanced server 2000 on the same server where exchange 5.5 running. Now I want to ask that if I upgrade OS then what will happen to exchange server? What are the precautions that I should take? I know that I can do this by taking backup of exchange but is there any way that I install without doing this??? Regards, Jawed Lashari IT Manager CSC