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Maybe some of your users reported that they receive messages from  Microsoft® Exchange user containing an attachment arrive as a winmail.dat file attachment in the Lotus Notes® client's mail file. These attachments are not able to be opened on the Notes client. Examination of the document properties reveals that the message was sent as a Content-Type: application/ms-tnef; name="winmail.dat".

This behavior is due to messages being sent from Exchange without MIME encoding turned on. Winmail.dat is attached to the message in uuencoded format. Information on how to prevent winmail data being sent to Internet users from MS Exchange is documented and publicly available from the Microsoft Support Web page, in the Microsoft Knowledge Base, article number Q138053:;en-us;q138053

For further information, you can also refer to Microsoft Knowledge Base article number Q196784:;en-us;196784

An enhancement request was submitted to Quality Engineering and functionality to decode winmail.dat attachments was added to Domino release 6.5.6, 7.0.2 and 8.0. The new functionality allows the server to convert the winmail.dat automatically. To enable the feature the following notes.ini parameters must be added to your Lotus Notes Domino Servers:



The fix also has some additional options:

-- This will keep the winmail.dat object as well as extract the regular attachments: TNEFKeepAttachment=1

-- This will append a rich text entry containing the message body: TNEFAttachRTF=1

-- This will set the log level (if needed): TNEFConverter_Log_Level=10

-- This will break a S/Mime signature (couldn´t break a S/Mime encryption) to extract the content: TNEFBreakSMIME=1


Sample implementation:








Related Information:

Attachments to messages received from the Internet are named as winmail.dat



This parameter is associated with crashes in Domino 7.0.2 and 7.0.2 FP1. For more information, refer to the technote titled "SMTP task crashes on Domino when TNEFEnableConversion=1 is enabled" (# 1252932)


You configure a Lotus Domino® database to use LZ1 compression and want to convert existing attachments to this algorithm to take advantage of its superior compression ratio. How can you upgrade the compression algorithm for existing attachments?


A tool called Lotus Notes Diagnostic is now available from the Lotus Sandbox. It is an unsupported utility which can be used to analyze NSD and other files resulting from a Lotus® Domino® server crash, hang, or performance issues.

IBM Technote


IBM announcet a new set of Domino capabilities to support mobile devices out-of-the-box called Lotus Notes Traveler. Initial support is for Windows Mobile devices, providing email, calendar, address book, journal, and to-do list. 

The marketing team has an overview page up on the IBM website , including some initial screen shots of the capabilities. 


Want to be certified for IBM Notes/Domino 8? The recertification exams are now available. One exam for sys admin (802) and  one for development (801).

Exam 801: IBM Lotus Notes Domino 8 Application Development Update
Exam 802: IBM Lotus Notes Domino 8 System Administration Update