I’ve seen a couple of questions about this since SP2 released, so I’ll give a shot at it. If you try to upgrade to E2k3 Sp2 on a server that has Intelligent Message Filter (IMF) version 1 installed, you’ll get this error message:
“Service Pack 2 for Exchange Server 2003 includes an updated version of the Microsoft Exchange Intelligent Message Filter. An earlier version of the Exchange Intelligent Message Filter has been detected on this system and this earlier version must be uninstalled before applying Service Pack 2.”
So, what to do if you’ve already uninstalled IMFv1 and you’re still getting this message? Well, you can double-check the same way the pre-requisite check does whether or not the system thinks IMFv1 is really installed.
This prereq check is actually looking into the registry. If IMFv1 is installed, then at HKLM\Software\Microsoft\Exchange there will be a value “ContentFilterVersion”. If this value is in the server’s registry *AND* is set to “0” (to indicate IMFv1), then the prereq will fail and you’ll see this message pop up.
Your best bet, if you’re sure you’ve removed IMFv1 properly, is probably to simply (and VERY CAREFULLY) remove this “ContentFilterVersion” registry value so that the prereq check will not find it – and will therefore assume IMFv1 is not installed. Don’t remove the Exchange key, just the ContentFilterVersion value. All the normal “editing your registry is dangerous” and “make a backup/export of the registry key before making any changes” stuff applies.