Another dumb mistake: installed VMware Server 1.8 on an Exchange 2007 SP1 server with the client access role installed. Instead of choosing the “custom” install option, as I usually do, I was in a hurry and chose “complete”. Halfway through the install, I remembered why I never blindly choose “complete”; VMware Server Management Interface. VMSI is a web-based management interface for VMware Server that when installed changes the preferences for IIS by enabling 32-bit ASP on 64-bit Windows. This breaks OWA (64-bit ASP) because IIS 6.0 does not support running 32-bit mode and 64-bit mode at the same time on 64-bit Windows.
Here’s the fix:
Disable 32-bit mode
cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 0
Register 64-bit ASP