Saturday, July 30, 2011


Article now on the official Mozilla support site:

Microsoft in their eternal quest for a competitive edge just will not stick to agreed standards.  This applies to mail as much as it does to anything else they make. Microsoft calls in Innovation,  and if you exclusively use their products it certainly can appear that way.  It is only when you have the temerity to use a non Microsoft product do you find that their innovation is not compatible with, well anything else really.

This is the case with the winmail.dat file.  It is a proprietary format for sending email attachments that only Microsoft programs  really understand. Others have spent their time and effort to try and get their programs to understand this format, decode it and present the content in a useful manner, but the Truth is that the problem is outlook.

This article on the office web site advises Outlook users how to fix the problem permanently.  Whenever you get one of these messages the best approach is to reply to the message sender that they have outlook incorrectly configured to send Internet mail and give them the link to the article on the office web site.  Most people simply don't know they don't have Outlook set correctly and will change things as soon as they hear that your can't open their attachments.

There is an add-on for Thunderbird which in some cases can read these winmail.dat files.  Lookout is not always successful, but it can usually display the attached files.


  1. Or forward to Gmail and access your attachment freely, Gmail appears to have no problems with the WINMAIL.DAT attachment.

    1. And that defeats the purpose of transparent information exchange. The person sending this mail is inconveniencing many thought either their thoughtless actions or their ignorance. Simply asking them to take corrective action is polite and efficient. Mucking around with add-ons, forwarding mail else where etc is a waste of time for you. But if you want to waste your time, that is certainly your prerogative.

    2. Jorn:
      Tried this with a winmail.dat that Lookout could not open. Gmail could not open it either.

      The major issue is with nested winmail.dat files, Lookout can only handle the first layer and just shows the inner winmail.dat

      Understand you're point, we'll try, but some people don't want to play nice.

  2. if every other email client, including online services like yahoo, gmail, aol can read emails from outlook fine, why cant thunderbird and Apple jump on board, considering how many mail servers are powered by MS Exchange and the amount of people using outlook in the corporate world...

    1. I for one see no problem. My personal opinion is I assume already obvious, but here it is again anyway. If Microsoft want to make mail clients then they and those silly enough to give them hard earned money to use it need to have a product that plays in the same sand pit as everyone else. It is not the responsibility of everyone else to invest in time, money and coding effort to work around the inadequacies of Microsoft's flagship mail client.

      The Fact that Microsoft don't care, and that significant parts of their user base are either to ignorant or self absorbed to fix the issue or complain to their supplier that they have a defective product is unfortunate.

      Please don't post complaints here about Thunderbird and Apple mail taking the high road. Take your complaints to the source of the problem. It is a very large multi national company that released a defective product.

    2. It appears that the Thunderbird developers and some Thunderbird users have an arrogant attitude problem that prevents them from seeing that Thunderbird is the problem. The developers need to make Thunderbird read the messages as was intended when sent. Thunderbird is not even in the top ten email clients used throughout the world. However, Outlook is #4 and #9 in ranking of email client use in 2020.

      #1 Gmail
      #2 Apple iPhone
      #3 Apple Mail
      #4 Outlook
      #5 Yahoo! Mail
      #6 Apple iPad
      #7 Samsung Mail
      #8 Google Android
      #10 Windows Live Mail