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You'll also find a pre compiled version of SpamAssassin for Windows that can simply be extracted and run here: http://www.jam-software.com/spamassassin/.
Note: These instructions The instructions below describe an obsolete procedure using tools which may no longer be available. They reportedly do not apparently work for SpamAssassin 3.4.1 using ActivePerl 5.20.2. ActivePerl now seems to force the use of dmake for Windows and some work will likely need to be done to make SpamAssassin compatible. We are seeking a working procedure for installation on modern versions of Windows. If you can help, please send a note to the dev list to get access to edit the Wiki.
This HISTORICAL installation procedure is for installing SpamAssassin in native Windows (not Cygwin) using ActivePerl (Tested on ActivePerl 5.8.9.827).
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