Does Outlook embed a MessageID or equivalent in its email elements?

Question

I want to automate Outlook so that I can download the "pieces parts" of email messages so that I can tie related messages together. I understand that email usually has a "MessageID" to serve this purpose, so that emails can be viewed in context, as "threads" in a newsreader are tied together.

Does Outlook have the notion of "Message IDs" in emails sent with it? I see that the elements that can be extracted (using automation) are Subject, SenderEmail, CreationTime, Body, SenderName, and HTMLBody. Is a "message id" or equivalent available somewhere, too?

Answer 1

Outlook tracks related messages by using Conversations.

In Outlook 2003, there is ConversationTopic (MAPI: PR_CONVERSATION_TOPIC) & ConversationIndex (MAPI: PR_CONVERSATION_INDEX). ConversationTopic is typically the message subject (minus prefixes - RE:/FW:, etc.), while ConversationIndex represents the sequential ordering of the ConversationTopic (essentially GUID + timestamp). See Working with Conversations on MSDN. ConversationIndex is explicitly defined on MSDN here.

In Outlook 2010, they added ConversationID (MAPI: PR_CONVERSATION_ID) which is derived from the ConversationTopic. ConversationID can be generated from the ConversationTopic as discussed here.

For more detailed info about the MSG protocol specs regarding Conversations see [MS-OXOMSG]: E-Mail Object Protocol Specification, section 2.2.1.2 and 2.2.1.3.