Why Exchange Server 2003 will not run on the x64-based versions of Windows Server 2003

This article describes why Microsoft Exchange Server 2003 will not run on the x64-based versions of Microsoft Windows Server 2003.

The x64-based versions of Windows Server 2003 seamlessly support the running of 32-bit programs. However, on the x64-based versions of Windows, all the kernel mode components must be native 64-bit components. Therefore, all drivers must be 64-bit components.

User mode 32-bit programs are run under Windows on WOW64. WOW64 is the 32-bit emulator. However, Exchange Server 2003 will not even be installed correctly under WOW64. The primary reason is that Exchange Setup installs the 32-bit driver for the Installable File System (IFS) that is incompatible with the 64-bit kernel.

Note The information described here does not apply when you run Exchange Server 2003 on 32-bit versions of Windows Server 2003 that are installed on 64-bit hardware. You can do this on 64-bit hardware that also natively supports the running of 32-bit operating systems and programs.

For more information about the system requirements for Exchange Server 2003, visit the following Microsoft Web site:For more information about the x64-based versions of Windows, visit the following Microsoft Web site: