Apple has updated its technote
on dealing with winmail.dat files.
After pointing out that winmail.dat files the result of emails containing rich text information sent “from a Microsoft email application (such as Outlook and the Microsoft Exchange Client)”, the technote advises:
To avoid seeing these attachments in the future, you ask the sender to deselect the email’s “Send to this recipient in Microsoft rich text format” checkbox or preference setting in mail client before they send the message.
Fortunately more immediate help is at hand.
OMiC is a plugin that can extract the files from a winmal.dat attachment on the fly. Since I last posted about it, it has got smarter.
It no longer uses the Save dialog, but decodes and presents the included files in Mail’s Attachment View:

It also now supports Panther (10.3), winmail.dat files with the wrong MIME type and Outlook’s iCalendar format.
It’s the kind of functionality that should be built-in to Mail.app but isn’t.
OMiC is shareware (5 euros = USD 6.30) and is available from the developer’s web site
. If you live in a Windows world, the money will be well worth it.

The word “rick” in the send sentence should read “rich.”
Quite so. Thanks.
[...] [Pause the podcast here and get a copy of OMiC which helps Mail.app and iCal play well with Outlook-generated email and calendar data] [...]
Thanks for pointing this out. I have a feeling I’m going to love this plugin.
A.