I have a C++ application that is sending a file to the Lotus client as an attachment. When I call the MAPI function ‘SendMail’ and pass it the file, the Lotus client displays the attachment, but the file extension is gone. I have looked in the code and when the sendmail function is called, the file has the correct file extension. When we use Exchange, the extension is not lost, so this seems to be only happening with Lotus. Any ideas would be appreciated.