View source for Known issues with Microsoft Office automation.

AutoIt provides a powerful integration and manipulation tool for the MS Windows environment and the WinAPI. Some features of Microsoft's Windows and Office products are proprietary and cannot readily be manipulated. Sometimes workarounds are required.  It should be noted that some of these issues change over different versions, resulting in "unexplained" errors or unexpected behavior. This pages is dedicated to identifying those issues, provide explanations and list solutions or workarounds.

Also, please note that since MS Office products function within the Windows environment, the behavior of different components may be mutually interdependent. Simply changing one setting in a specific box, may not have same or desired effect across all platforms and all versions. The uniform use of Windows 10 should reduce these issues.

== Microsoft Outlook Email WINMAIL.DAT ==

=== The Problem ===

Microsoft mail products such as Outlook, Office 365 and Exchange may send mail messages in a proprietary format known as TNEF that only other Microsoft products accept. Find out how to configure your Microsoft product in the list below so it doesn’t send messages in the TNEF format.
From [https://capsulecrm.com/support/microsoft-tnef/ Capsule CRM]

Email sent using Outlook may be formatted using the Microsoft proprietary TNEF format. Sending the mail appears correct, but the recipient typically receives and email attachment in winmail.dat format. A quick search will indicate just how wide spread this problem is.

=== The Cause ===

Transport Neutral Encapsulation Format or TNEF is a proprietary email attachment format used by Microsoft Outlook and Microsoft Exchange Server. An attached file with TNEF encoding is most often named winmail.dat or win.dat, and has a MIME type of Application/MS-TNEF. The official (IANA) media type, however, is application/vnd.ms-tnef.
Fronm this page: [https://en.wikipedia.org/wiki/Transport_Neutral_Encapsulation_Format Wikipedia.org Transport Neutral Encapsulation Format]

==== Look out for ====

Microsoft uses "aliases" for the TNEF model.
These include "Sending in Rich Text Format". The mail is not sent in RTF but rather forces TNEF encoding.

=== Solutions ===

The preferred solution appears to prevent MS Outlook from sending TNEF encoded messages. There is no control over the decoding of the message as received. By preventing the Senders use of TNEF, this problem may be mitigated.