Outlook 2010 & Aid4Mail 2.4
Microsoft Outlook 2010 by default allows users to save email messages externally as a MSG, OFT, HTML, MHT, or TXT file format. Microsoft Office programs can have add-ins installed that extend the available functionality of the software. Verifying if any add-ins exists in Outlook can be done by checking the SOFTWARE and NTUSER.DAT registry hives for the following folder path: Microsoft\Office\Outlook\Addins.
Other applications can access email using a Messaging Application Programming Interface (MAPI) connection. One example is Aid4Mail an email conversion program from Fookes Software that adds additional file format export options such as PDF, ZIP, XML, and others. The file formats and export paths used by the application can be found in the C:\Users\\AppData\Roaming\Aid4Mail\Aid4Mail.ini file.
Not every application using MAPI connections will leave as obvious of an artifact thus leaving it up to the specific developer on what email formats will be available. One option is to determine what specific DLL’s are used by an executable such as C:\Windows\SysWow64\mapi32.dll or C:\Program Files (x86)\Microsoft Office\Office14\olmapi32.dll for example. Another is using a time line approach to determine if a MAPI configuration was abnormally accessed by looking for creation and deletion of C:\Users\\Documents\Outlook Files\~Outlook.pst.tmp without other normal Outlook behavior.