I got a legacy 3rd party application that uses Outlook to send out Email - the new emails appear in the Outlook Outbox and gets delivered when Outlook sends email (either automatically by settings or manually using the send mail button). I do not know what API it uses, but I suspect it could be either MAPI extended or Outlook Object Model, etc - but it is not using MAPI simple as there is no need to "allow" the outgoing email. However, the weird thing is that it will only work if Outlook application is running! This causes problems because the user would have to login to the system and then manually start Outlook in order for the integration to work. I tested some MAPI simple/extended clients I found on the web, and it appears that they are be able to work without Outlook running - i only need to define Profile to use. I am stuck to this application as I do not have the source code, nor can I replace the mailer since it is integrated with an ERP system. If you know what is going on, please let me know, thanks.