.DAT File Extension

Data (General)

Data File
So you want to open that .dat file that you've found on your computer or have been sent by e-mail. Well, I hope you're ready for some bad news! The .dat file extension simply indicates that it's a data file and could potentially have been created by just about any program in existence.

Want some more bad news? The .dat files happen to be one of the most common file extensions in computing.

Now for some good news, maybe.

Firstly, if you have found the file on your computer, it's found location may give you a clue as to which program created it, which in turn may provide a clue as to which program can open it. Also, the date and time that the .dat file was created/last modified can sometimes help if you know what software you were using at that point.

And some more good news, maybe.

As the format of the data in .dat files is often specific to the software that created it, it's sometimes possible to open the file in a text editor such as notepad or editpad pro (for larger files) and manually scan through the contents looking for clues. Remember, never save the file after opening in a text editor, as you will probably lose the file's original format.

So in summary, there's no way of knowing which program can open a .dat file, as the .dat extension simply means data.

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Comments (11)
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Rob Hall
2006-05-29 10:07:27
Does anyone know which software is best for backing up a 2.3gb .dat file?
2006-05-30 10:35:29
just drag and drop using windows explorer
2006-05-31 13:39:13
google around for some proper backup software, loads of free ones that will do the job fine. forget windows explorer, it'll give you headaches.
tp _at_
2006-06-19 20:13:37
I have a .dat file as an attachment in an email, is there any way at all I can find out what this file is?

Jay /
2007-03-05 12:18:05
Have you tried the above steps to identify the file?
2007-03-10 15:34:37
Try it, I doubt it though. Are there any other clues in the archive?
2007-03-10 23:49:39
Well, it worked... I renamed the files, changing DAT to MPG and Quicktime opened them up and it played. Cool!
2008-09-04 17:45:10
I'm sort of trying to do the reverse...

I need to change a jpg into a dat file. I've tried renaming it in explorer and it just stays as a jpg with the file name now containing .dat ???
2009-01-30 08:10:11

It's possible that you have file extensions hidden.

If so... under Explorer's Tool >> Folder Options >> View tab, ensure that "Hide extensions for known file types" is unchecked.
Rose Kallas
2009-11-03 14:23:37
I have an attachment that I can't open. It states Name: Winmail.dat Type: Unknown file type 5.67KB.

I received these winmail.dat attachments from one person (sending from Outlook Express) and I am never able to open. I called Dell Tech Support & they will charge $69 to download software application. What is the correct software on line that I can download free to correct this issue?
2009-12-26 16:29:13
Hi I've received an email with a file attachment it says it is winmail.dat when I click to open this it says I need to find a file to open this? I am a novice on pc so haven't a clue how to go about this, please tell me how I can open this, thank you.