Did you get an email with an attachment that you can not open? It has a .DAT extension and when you open it you do not know which program to choose? Do not worry, it’s a common problem and it happens to everyone sooner or later. That’s why today we see how to open a DAT file to read it. Are you ready? Let’s begin…

Files with the DAT extension can be files of any type that are not recognized correctly during the transfer between one email server and another. They can be pdf files, word files or multimedia files like images or music, but you can not trace the file type from the extension because it was changed during the transfer.

How to open a DAT file

If you can not go back to the type of file contacting the person who sent it to you, you’ll be pleased to know that there are several ways to go back to the file type of a DAT file, so you just have to try one.

Method 1 – Try your luck 🙂

The first is the empirical method … What does this mean? Try changing the extension by hand until you can open the file with the correct program.

First you have to save the file and check its size. At this point, you can already understand if it is an office file or a file of another type. Office files, both Microsoft Office and Open Office or Libre Office, have a small size, in the order of a few dozen kilobytes. If the file is larger, it is probably neither a text file nor a spreadsheet and could be an image, a PDF file, or a file of any other type.

Start to change the file extension in one of the formats known as (PDF, JPG, MP3 etc.). When you try to open the file you will understand that the extension is correct if the file opens correctly.

Method 2 – Linux gives you a hand

The second method is to use a linux command that provides information on the type of file. How does it work? It’s very simple … Every file contains inside (right at the beginning) information on the type of data it contains. The extension is not the element that distinguishes the content but only an expedient that goes back to the old DOS.

The linux command that provides information about the file type is … “file” followed by the file name. All you need to do is copy the file to a flash drive or download it to a computer with Linux and run the command from the terminal:

$ file file_scaricato.dat

How to open dat file

As you can see from the image above, despite the DAT extension the file is correctly recognized as a jpeg file.

Method 3 – Online control

The third method is perhaps the least complicated. It consists of using an online service that analyzes the file and as a result, communicates the type of file. The service is called CheckFileType and in practice, it is the file command seen in method two, only that it is not necessary to have a PC with Linux.

All you need to do is open the checkfiletype.com page, upload the file and click on the Check file type button. After a few moments, depending on the size of the file, the answer will appear on the screen.


As you can see it is really easy to recover a dat file and open it even if you do not know its origin. By using one of these methods, you will surely understand how to open a dat file even if you do not know what it contains. I hope I have been helpful and I invite you to comment on my articles.

See you soon


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