Opening *.dat files

The DAT extension has been in use long before there was an Internet and email. A dat file can be ASCII text or Binary or any other format the creator can think of. As a result, association with a particular program may or may not work in all cases.

The choice of the dat extension for email was a very poor programming decision.

I am not familiar with how you create them, but if I were sending things that the majority or recipients can’t read, I would find a better way to do it. Likewise if someone sent me something and told me I have to do this and this to read it, I would tell them not to send me anything in that format.

I had the same problem...which was whenever I sent an attachment to a(n) email, via outlook, the folks on the other end received the attachment as a winmail.dat file. The problem has something to do with msoft's enriched text format. The only solution I could find, to date, was to set my system to send the receipients ONLY plain text emails...not the 'msoft enriched text format' that outlook wanted to send them. I didn't do anything special with outlook when I set it up, ie no special tweaking, so I assume that the enriched text format is being set 'stock' out of the box so to speak...and that the folks receiving my emails arent' using outlook so their 'puters don't understand the enriched text thingy. I hope this helps.... I'll try to post more info on this later.....I'm at work now. ..ssshhh...don't tell my boss!

Did anyone actually supply an answer?  I have the same problem, but it seems no one wanted to answer the actual question - i.e. how do you open it?  Instead they just chose to tell how to prevent it - which I don't care about right now.

AFAIK, you will not find the answer you are looking for.  DAT files are essential files utilized by applications and are not intended to be, "opened" or "read" in the sense you might be thinking.  For example, many antivirus providers use the .dat extensions for periodic updates of their signature files.  Open these in a text editor and you will only see graphic symbols of the programing language of the file.

Bottom line, if you are receiving .dat files as attachments in email there is a better than even chance the sender is not sending or attaching the file properly.  There is no email program I am aware of using this format to compose or send attachments.  If they were, recipients would be unable to read or view them.  Even the most proprietary of email providers (AOL, for example) utilize formats that can be universally accessed.  I might suggest that you contact the sender(s) of these files and determine what  type the attachment (text documents, image files, sound file, etc.) was "supposed to be" and go from there.

Thanks for the informational reply.  I am guessing that the person with this problem (in addition to me) was receiving email messages from a person with an iMac.  I have one at work which runs OSX and Office X.  If you don't put the file extensions (i.e. .doc  .xls  etc.) your attachments come across in the email in this .dat format.  I know one problem with OSX Panther is that when sending an attachment in Word format you not only need to put the .doc extension on the attachment, but you also need to remove the "resource fork" before sending the email or once again your PC friends will not be able to open it.  I think Jaguar is supposed to get rid of the resource fork problem.