This article provides an answer to the query: Does GFI MailEssentials integrate with Internet Message Filter (IMF)?
You can run both GFI MailEssentials and Microsoft's Internet Message Filter (IMF) concurrently and have two spam detection engines.
GFI MailEssentials drastically reduces false positives resulting from IMF. GFI MailEssentials' automatic whitelist management feature ensures that the IMF does not block emails from known senders and emails with keywords which are normally used in your day-to-day business.
In order to take advantage of the whitelist functionality provided when GFI MailEssentials is installed on the same machine as Microsoft Exchange with IMF enabled, GFI MailEssentials needs to be configured to move emails to the user's Junk Mail folder.