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.dat files 1

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officework13

Technical User
Aug 29, 2002
37
CA
i have received several emails with the extension .dat When i double click on them they start up my windows media player but then i get an error message indicating that it can not support the specific file. What type of programs are there that would open this type of file.

 
.dat files can be most anything, if the sender can't tell you what it is, you probably shouldn't open it.

If you choose to ignore the above advice, you could start by opening it with notepad. You may or may not find some useful info to at least tell you what it is.
 
smah is 100% correct. Never blindly double click an attachment in e-mail if you don't know what it is or you could spread a virus. This is a website that use to find out extensions that I don't know. P.S. could be McAfee anti-virus virus definition file.
 
Which mail client are you using.

Chances are the file that you keep getting is named winmail.dat. If it is, then the problem is probably at the sender's end.

Please give more info.
 
i use MS outlook
the file name was received from a freind and so i do not suspect that it is malicious (virus)

the name of the file is ATT00003.dat and it is 122kb

my friend is gone and i am unable to contact him on the program that was used.
 
What you are getting is a file in the Transport Neutral Encapsulation Format (TNEF).

This explanation from MS:

A TNEF-encoded message contains a plain text version of the message, and a binary attachment that "packages" various other parts of the original message. In most cases, the binary attachment will be named Winmail.dat, and may include:

The formatted text version of the message (font information, colors, and such)

OLE objects (embedded pictures, embedded Office documents, and such)

Special Outlook features (custom forms, voting buttons, meeting requests, and such)

Regular file attachments that were added to the original message

When a message containing TNEF information is received by a mail client that does not understand TNEF, there are three common results:

The plain text version of the message is received and it contains an attachment named Winmail.dat. The Winmail.dat attachment does not contain any useful information when opened since it is in the special TNEF format.

The plain text version of the message is received and it contains an attachment with a generic name such as ATT00008.dat or ATT00005.eml. In this case the client is unable to recognize the TNEF part of the message, and is unable to recognize the Winmail.dat file name, so it creates a file name to hold the TNEF information.

The plain text version of the message is received and the client ignores the Winmail.dat attachment. This is the behavior found in Microsoft Outlook Express. Outlook Express does not understand TNEF, but it does know to ignore TNEF information. The result is a plain text message.


What to do?
Detach the file and open it in browser. Chances are it will open.


 
i tried to save it and open it in internet explorer but that did not work. it started windows media player instead.
 
If you're double clicking the file, it will start media player because that is the progam that you computer has associated with *.dat files

You need to either start your browser then do a File/Open to open the file
or
Click on the file. Press and hold your shift key and then right click on the file. There should be an "Open with..." option now. Chose the open with... Scroll down to iexplore (or whatever your browser is) Uncheck the Always use this program box if it is checked. Click "Ok"
Mike

Before: After
[morning] [bugeyed]
 
Right click on the saved file and select open with, then pick internet explorer from the list.
 
i have saved it to my hdd and used open with ie and it reverts to windows media and i get the error. i then changed the associated program to Internet explorer and tried to open it and it did not open

 
i also tried to open in in word as well as notepad and i get a bunch of symbols.
i tried to open in in programs for viewing pictures.

it is supposed to be some sort of video clip
 
Such DAT files are usually MPG files. Try chaning the extension to MPG and see if it will play. If it doesn't, then either you don't have the right codec installed or there is extraneous info in the file. There is some sort of app called VCDgear that strips the unwanted information. You would have to search for it.
 
Thank you for all the help nothing has worked yet and i do not wish to use any more resources on this issue. i will contact the individual who has sent me this when they return

thanks again all that gave me some input.
 
I've had the same thing. The win.dat attachments seem to be generated by Outlook when sending other attachments eg: spreadsheets, docs, whatever. When received by non-Outlook programs they can show up as "dat" files. (don't you just love MS?) If the sender uses plain text format or HTML, this seems to solve the problem. Since passing this on to my "Lookout" using friends, this has solved the problem.
Good luck.
 
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