Here is what is allowed to run on what Regarding the Exchange 2003 and Windows Server 2003 question, I think the following chart might help: Exchange can be installed and run on[1] Supported Active Directory Environments[2] Exchange Version Windows 2000 SP3+ Windows Server 2003 Windows 2000 SP3+ Windows Server 2003 Exchange 5.5 with SP3 Yes No Yes Yes Exchange 2000 with SP2 Yes No Yes Yes Exchange 2000 with SP3 Yes No Yes Yes Exchange 2003 Yes Yes Yes Yes Goran Jovanovic The LAN Shoppe 2345 Yonge Street, Suite 302 Toronto, Ontario M4P 2E5 Phone: (416) 440-1167 x-2113 Cell: (416) 931-0688 E-Mail: gjovanovic@xxxxxxxxxxx -----Original Message----- From: David Liles [mailto:dave@xxxxxxxxxxxxxxxxxxx] Sent: Thursday, July 24, 2003 9:38 AM To: [ExchangeList] Subject: Exchange 2000 on Win 2003 Server Quick question.... We are replacing our current exchange server which is Exchange 2000 on Server 2000. We would like to know if it is possible to run Exchange 2000 on a 2003 server or are there enough differences with the 2003 OS that would advise against such a build. Thanks