Holy crap, Microsoft is annoying. Just when I thought I'd outgrown the whole "Micro$soft sucks" phase, they find another way to piss me off. Outlook and Exchange Server add stupid attachments that no other email program can read. I don't care so much about the formatting information, but it turns out that if Outlook users attach a real file to their email, it sometimes winds up in the winmail.dat file too. Of course, so many people use crappy old Outlook that they don't think it's their problem if your email program that does things properly doesn't read their god-damned obfuscated files.

If you can't convince the sender to use a non-braindead mailer, try this.