I am in the process of upgrading our network to Windows 2000 and I have an Exchange 5.5 server running on NT 4.0sp6a. I don't have the luxury of extra servers to build a new Win2k/Exchange 5.5 and restore so.... What I wondering is are there any problems upgrading the existing NT 4.0 to Win2k that is running Exchange 5.5? Any help on this subject would be appreciated.