If you have remnants of Exchange 2000 on Windows Server 2003, even after an uninstall of Exchange, you may get warnings about the IFS driver. The Exchange Installable File System (ExIFS) exposes bits of the Exchange information store via the file system. Running Exchange 2000 on Windows Server 2003 is not supported by Microsoft and doesn’t work. The IFS driver is loaded by the EXIFS service. We arrived at this sorry state by trying to install Exchange 2000 on Windows Server 2003. An error will show up in the event log:
The IFS driver can be removed by deleting the EXIFS registry key:
For more details and a list of other registry entries that you might consider cleaning, see How to manually remove an Exchange 2000 installation