Decoder Tools for Outlook

Last reviewed on November 8, 2014   —  No comments yet

If some messages arrive from the Internet looking like scrambled eggs, then you need to save each one as a file, then decode it. This is much less of a problem with current versions of Microsoft Outlook than it was with older versions of Microsoft Outlook and Exchange Messaging.

There are two types of files that may need decoded: uuencoded messages, that for one reason or another did not get decoded by Outlook and winmail.dat files that result from using RTF message format.

The TNEF/winmail.dat decoder tools can be used by non-Outlook users to "crack open" winmail.dat files to recover attachments.

Tools | Notes | More Information



Utility to decode attachments sent by Outlook that arrive as Winmail.dat files because you sent in Rich Text Format.

Rot-13 for Outlook

Rot-13 Addin is Rot-13 encoder/decoder for Outlook.Free. Version:

TNEF's Enough

Tool for Macintosh computers to decode the Winmail.dat attachment sent in Rich Text Format messages.

Winmail Opener

Winmail Opener is a small and simple utility that allows users to view and extract contents of TNEF-encoded messages (winmail.dat). Version 1.4 - Free.

Winmail.dat Reader

Open, convert and save the files on winmail.dat email attachments sent by Microsoft Outlook and Exchange. Easy-to-use graphic interface (no command-line tool). Displays the original message subject and body. Free.


Includes UUencode, BinHex and MIME support, so you can extract attachments from messages that you've saved as files.


More Information

  • OL2000 Information About Outlook and Encoded Messages
  • Decoding Internet Attachments – A Tutorial

About Diane Poremsky

Diane Poremsky
A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

Please post long or more complicated questions at Outlook forums by

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