Can I run Microsoft Exchange Server 2003 32-bit edition on the 64-bit version of Windows Server 2003?

A. No, this configuration isn't supported. Remember that 64-bit OSs can't run 32-bit drivers. Exchange 2003 has the Exchange Installable File System (ExIFS) 32-bit driver that runs as a kernel mode driver. You'll need to wait for a 64-bit version of Exchange. Most 32-bit software can run on a 64-bit OS via the Windows on Windows 64 subsystem, which provides an emulated 32-bit environment, but this interoperability doesn't apply to drivers.