Reply To: winmail.dat
I use Thunderboid and Win 7 — but can’t say I’ve run into this.
Does the name of the file get changed only went sent from the one user? Maybe something at their end is making the change. You could ask them to email themself one of the files, and check on what they receive back.
If it is happening at your end, it could be in your email server — but then I would think the copy from the fellow board member also would get changed. But that would also apply if something, like your virus scanner was playing games.
Is it only a name change to the attachment? If so, then you could change the name back to what it should be and see if it opens OK.
A Google search for [ winmail.dat attachment ] seems to point the finger at the sender for trying to send a file with RTF formatting that your end does not understand.