Please help me resolve this long standing problem. I am currently in the process of migrating our users to Windows 2000 and Windows XP from Windows 98. At the completion of this process I also expect to migrate my servers from Windows NT and Exchange 5.5 to Windows 2000 and Exchange 2000. I have migrated one of my workstations to Windows XP and Office 2000 as a test machine. However, I can't seem to be able to connect to the Exchange server 5.5 server from my Outlook 2000 client with Windows XP Professional. Whenever I try to resolve the user name in Outlook I get an error message saying "Name could not be resolved. The operation failed". I have checked TCP/IP communication and everything seems to be working fine - DNS, WINS, RPC. I also checked the RPC binding order in the registry and it looks fine. When I try connecting to another Windows 2000/Exchange 2000 test server that I have there is no problem. However, we have not made the necessary preparations to migrate the server environment to Windows 2000/Exchange 2000 in the live environment. Please help. Mike