open winmail.dat files on your mac

Do you have friends who send you emails announcing the next big party, but you can’t see the invitation because there’s only a winmail.dat thingie? And on your mac you can click it, but then you get a message about how you and all your mac programs can’t open it?

No need to miss the party! There’s a handy little freebie called TNEF’s Enough that will dig into that weird winmail.dat attachment and let you save whatever your Windows-challenged friends send you. I just discovered a .doc file hiding in my latest winmail.dat, and a lovely invitation to an upcoming party. This time around I get to go too. 😉

Thanks so much to Twister Mc for the great tip.


If you read the comments to this post, you’ll see that I got another tip for solving this problem: OMiC, a plug-in for the Mail application itself.

Update again… 19 Dec 2009

OMIC is apparently now called Letter Opener (renamed for meaning: excellent idea from the marketing dept! 😉 ). Looks like it’s available for lots of OSX versions, from Panther 10.3 through Snow Leopard 10.6.

Letter Opener

OMiC is shareware, so you can use it “for free”. But hey, pay the $29.95. After all, you get a big jump in convenience over TNEF’s Enough. Because OMiC works right in Mail, you don’t have to open up any other program to see into those mysterious winmail.dat files. Automagically, you just see the original file that your friend sent using Windows and Outlook: In the body of the Mail message, I saw a link to the .doc file, clicked it, and Word launched to open it. Very nice.

And OMiC’s developer appears to be pretty active. 😉

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17 Responses to open winmail.dat files on your mac

  1. Christopher says:

    You can also try out OMiC, a Apple Mail Plug-in which process winmail.dat files in Mail.

    OMiC also support nested messages, VCF, ICS in winmail.dat files which TNEF’ Enough can’t export, and also handle long filename better.

  2. noah little says:

    Thank you Christopher, will check that out right away. If it does the job better, I’ll even pay for it. 😉

    Alas, the installer choked. That’s a no-go for me. Too bad, it would have been very handy.

  3. Christopher says:

    Noah, the current version don’t run/install on leopard. Just write me a line and I send you the link to the beta which support on leopard..

    • Art says:

      I am also running 10.4.11 and the open letter would not install saying there wasn’t anything in the download. I will pay if it works. I’m the only mac user at my company.

      • noah little says:

        Hey Art – Give the developer of Letter Opener a quick note at – he’s quite responsive and will be able to help you out with that download better than I can here. Best of luck, brave one-guy-with-the-mac!

  4. noah little says:

    Hi Christopher, thank you for the follow-up, very kind of you. I’m running Tiger though. Oh, wait a sec, I tried to install it on machine with 10.3.9, but that supposed to work too…

  5. Christopher says:

    Noah, you are right, the installer of 1.7.7 has also problems with 10.3.9. The beta of the upcoming OMiC 2 already fix this, just write me a line and I send you the link.

    • rosamund says:

      THANKS, RM

    • Teresa says:

      Hi Christopher,

      I was able to install letter opener on my desktop (running leopard) no problem. It installed on my laptop also running leopard but it will not work here. It opens the app and immediately quits.


      Thank YOU!

  6. noah little says:

    Thanks Christopher, that did the trick. Nice plug-in.

  7. Kevin says:

    I tried it in Leopard and it will not work. I assume they are working to fix this?

  8. noah little says:

    Hey Kevin. Do you mean OMiC? Looks likes there’s a beta out for Leopard, check the dev’s blog:

    You can contact him directly to get the beta, he was very active giving help previously:

  9. Ron says:

    I received a file on my Mac and can’t open it. I downloaded TNEF 2.0 to open the file, but still can’t get the file to open. Can anyone help. Thanks

  10. noah little says:

    Hey Ron, got any more details on that problem? How far did you get? Any error messages?

    Another option, if you’re using Apple’s Mail app, is to download the OMiC plug-in. In the end that’s what I went with. Good luck!

  11. Sue May says:


  12. Di Di says:

    I also have leopard and wanted to know if you can help me out with the winmail.dat file i just received?? Help please!

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