Email Converter is one of the popular tool which quickly convert multiple types of email into different formats. This tool doesn't damage the original file which conversion to other formats and is simple to use, ant type of users can easily handle it.
It supports DBX, PST, EML and MSF as input formats, and provides you DBX, EML, PST, MSG, RTF and HTML as Output formats. You should try its free demo version first before purchasing the software.
See more info at:-
http://migrateemails.com/2016/03/15/complete-solution-for-email-conversion-email-migration/