I am developing an app to send MAPI mail from vb.net, and have experienced many of these same issues over the past week. I must send MAPI and not SMTP, as many of the junior managers in my company do not get SMTP mail addresses. After a week of experimentation and advice, I finally got past the errors described above, but still have a problem. I get past the Logon ok, but when I hit the following line to start a message (with the arrow), it simply hangs indefinititely. Is there something that must be set up on the Exchange 5.5 box? Is there a log file on the Exchange box where I can see what is happening? Here is the code: ' start the session Dim objsession As Object objsession = CreateObject("mapi.session") Dim profileinfo As String profileinfo = "exchangeserver" & vbLf & "mailboxalias" objsession.Logon("", "", False, True, 0, True, profileinfo) ' start the message Dim objmessage As Object objmessage = objsession.Outbox.Messages.Add '<================= objmessage.subject = "This is a test." objmessage.Text = "This is the message text." ' add receipients Dim objRecipients = objmessage.Recipients objRecipients = objmessage.Recipients.Add objRecipients.add("RecipientAlias") ' check for valid recipient objRecipients.Resolve() 'Send the message objmessage.Send() 'Logoff objsession.Logoff() objsession = Nothing Any assistance would be greatly appreciated.