1. Technology
You can opt-out at any time. Please refer to our privacy policy for contact information.

What is a DAT File?

How to Open, Edit, & Convert DAT Files


Question: What is a DAT File?

Did you find a DAT file on your computer and wonder what program should open it? Maybe someone emailed you a DAT file but you're not sure how to use it. Perhaps you tried to open the DAT file but Windows told you that it could not open it.

Before you can open a DAT file (assuming it's even a file format that's intended to be viewed or edited), you'll need to determine what kind of file the .DAT file extension refers to.

Answer: A file with the DAT file extension is a Data file.

Other types of files that use the DAT extension include VCD video files and some email program file attachments. The game Minecraft also uses the DAT extension for a variety of purposes.

You might also see a DAT file alongside a DLL file. These DAT files might be simple help files or might be necessary for the DLL, and associated program, to work properly.

If you know of any additional file formats that use the .DAT extension, please let me know so I can update this information.

How To Open a DAT File

The easiest way to open a DAT file is to double-click on it and let your PC decide which default application should open the file. If no program opens the DAT file then you probably don't have an application installed that can view and/or edit DAT files.

Warning: Take great care when opening executable file formats received via email or downloaded from websites you're not familiar with. See my List of Executable File Extensions for a listing of file extensions to avoid and why.

If the DAT file is actually a generic "data" file, the program that generated the DAT file is your best bet for opening it, but you should try a text editor if that doesn't work (see the Tip a few paragraphs down).

DAT files that are video files can be opened with a program like VCDGear or CyberLink PowerDirector, among others.

A DAT file you receive as an email attachment, maybe in the form of winmail.dat or ATT0001.dat, is a malformed attachment from a Microsoft email client like Outlook, Outlook Express, Windows Live Mail, or Microsoft Exchange. Download the file to your computer and then extract the proper attachments from that DAT file using the free Winmaildat.com service or the free Winmail Opener program.

Bitcoin-QT uses a file by the name of wallet.dat as the Bitcoin client wallet file.

If you know anything else about DAT files, please let me know so I can update this page.

Tip: Use WordPad or another text editor to open the DAT file. Many files are text-only files meaning no matter the file extension, a text editor may be able to properly display the file's contents. Depending on where the DAT file came from, it could be a generic text-based file so this trick is worth a try.

If you find that an application on your PC does try to open the DAT file but it's the wrong application or if you would rather have another installed program open DAT files, see my How To Change the Default Program for a Specific File Extension guide for making that change in Windows.

How To Convert a DAT File

While it completely depends on the type of DAT file you're working with, there are two main ways to attempt to convert a DAT file to another file type:

The first option involving opening the DAT file in its native program is preferable because it's both easier and will probably result in a more accurate file conversion. Of course if you don't have a program that opens DAT files, a third-party file conversion tool (the second option) could be very useful.

Also remember the advice about winmail.dat and ATT0001.dat files several paragraphs above if an email attachment is the source of your DAT file.

Important: You can't usually change a file extension to one that your computer recognizes and expect the newly renamed file to be usable. However, in the case of a DAT file you received via email that you know is supposed to be, say, a Word document file, but it instead ends in the DAT extension, try renaming it to the correct extension (e.g. DOC or DOCX for Word, JPG or PNG for image, etc.) and giving that a try. Before you can rename a file extension, you'll have to make sure that Windows is configured to show them properly, which is explained here.

Still Having Problems Opening or Using a DAT File?

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the DAT file and I'll see what I can do to help.

©2014 About.com. All rights reserved.