Winmail.dat sent to some recipients from address book

[VladimirMedic]

I’m making an addIn for Outlook(2003 and 2007) which is changing the body and the subject of the message that is sent in the ItemSend event handler. I have a problem with recipients receiving winmail.dat file for html content. I have found on forums that to avoid this I need to set UseTnef property to false for the message and PR_SEND_RICH_INFO for the recipients. I have managed to do the former via Extended MAPI, but I’m struggling with the later. Using McfMapi, I can see that PR_SEND_RICH_INFO in the address book for the contact is false, but when I check the recipients table (GetMessageRecipients) and iterate trough properties, for some recipients the property tag is 0x34a0000a which indicates an error or missing property. After the message is created in outbox, for the recipients that had error tag this property is set to true and they receive winmail.dat in their clients. I even tried to change property tag to 0x3a40000b and set it to false, call on ModifyRecipients with the changed table as parameter but no effect.

Do you have any idea or advice that may help me with this problem?



Thanks in advance



Vladimir Medic