Winmail.dat is created when the sender uses "rich text" (RTF) format instead of either Plain Text or HTML. Microsoft Outlook might switch to RTF in some cases because it wants to support special features of Exchange Server related to appointments. I don't know whether the sender can switch the format back to HTML or plain text before clicking Send. You might ask them to try that.

Meanwhile, once you have the thing, hmm...

There is an add-on mentioned this this support article to decode the winmail.dat attachment (I haven't tried it myself): https://support.mozilla.org/kb/what-winmaildat-attachment

I also noted some other tools in a web search, but I have not tested ANY of these myself: https://www.google.com/search?q=winmail.dat+%28decode+OR+convert%29

Hi,

as mentioned already, I have bene trying everything out there for years. Nothing works. If you google it, you will see others have this issue too and have given up on it. And its very hard to find these posts, because they have given up complaining.

This is not the traditional issue with winmai.dat. The senders already have had this option set to send mail as html (and not as rtf). And their mail contents comes fine.

But it appears that outlook still encodes the ics as winmail.dat. To re-iterate, I have already tried 3 addons (2 years ago and again this morning before the post). Ditto with external winmail.dat readers. They sll show it as blank.

But gmail works fine. if you send me your email address, I can forward one to you. rohit at cfl dot co dot nz

BTW, I tried uploading .eml here but the site rejected it because it was not an image :-)

Okay, I tested this out in Outlook 2010; I assume later versions are similar.

I can forward a calendar appointment as a .ics in two different ways (as shown in screenshot):

(1) From the day/week/month view, first click the appointment to select it, then on the ribbon, Calendar Tools>Appointment section, click the little triangle below the Forward button and choose Forward as iCalendar.

(2) With the appointment open, from the Appointment section of the ribbon, click the little triangle to the right of Forward and choose Forward as iCalendar.

Those methods yield an attachment that ends with .ics and has the correct internal format.

Using other methods generally yields an attachment with no visible extension, but when you save it to the file system Outlook adds the .msg extension and consistent with that, it is an unusable binary file.

So you may be looking for the wrong converter. This article mentions one that is said to handle .msg files: http://kb.mozillazine.org/Import_.MSG_files

Still no luck. Even if I save the email file and import it again, its still the same. winmail.dat remains intact. I think you are missing the point.

When someone sends me the invite (not when I save it from outlook to a file), its not viewable.

Here is one link to show its not just me.

https://josephhall.org/nqb2/index.php/icstbird

The only thing is Show All Body parts addon still does not help. Maybe it did for him then.

The bug is recorded here, its been there since 2009. Surely its more important than anything else. Because the people that receive these emails dont know what they are missing....

https://bugzilla.mozilla.org/show_bug.cgi?id=505024

It says that things work fine if lightning is installed - this is not true either.

Sorry, I thought from your original question that someone was sending you an ICS file, or what they thought was an ICS file, as an email attachment. Now I understand they are sending you an Outlook meeting request, which obviously is a completely different thing.

I don't know anything about that and will look into it when I can, but hopefully someone else will jump in before then.

I believe it is an ics file encoded as winmail.dat. Because gmail shows it as an ics file. It calls the attachment invite.ics. But thunderbird only shows winmail.dat

Thanks anyway.

In another thread here, I saw a tip on Lightning that might or might not help with the meeting requests you are receiving: http://forums.mozillazine.org/viewtopic.php?p=13030631#p13030631