How to open .dat files

Did you receive an e-mail with .dat files attached? Don't panic: in this guide we explain you what they are and how to open them. Find out with Libero Tecnologia!

If you often use e-mail, you will undoubtedly have come across .dat files. In fact, it happens that some documents, when attached to an email, can have a particular extension - the .dat format - and are rather difficult to open. Are you wondering what exactly .dat files are and how to read them? We explain everything in this short guide.

What are .dat files

The .dat files generally identify generic data files that can contain any kind of information: text, images, spreadsheets, but also music or multimedia files. In order to open them, you have to find the right extension and, consequently, the program that can read it.

How to open a .dat file

As already explained, in order to open a .dat file correctly, the first thing to do is to know the application that created it. An important clue may come from the file extension: if it exceeds 2MB, it is most likely a multimedia object; if it is only a few KB, you may be in the presence of a document. Try to identify the file format by right-clicking on it if you are using a Windows operating system, or by clicking on the command key if you are using a Mac operating system. Now try to open the file with the different programs on your computer, which will appear in a sort of list. Make several attempts (Word, VLC, PDF): when you have found the right one, you will be able to read or play the .dat file perfectly. Your task, however, does not end here, because you will have to rename the .dat file with the appropriate extension: just press the right button, select "Rename" from the menu, delete the .dat extension and replace it with the one of the exact file type the document belongs to (.txt, .doc, .pdf)

Open a .dat file with ad hoc applications

If you don't have enough time to try opening a .dat file with the applications on your computer, you can use one of the many programs created for this purpose.

Winmail Opener

This is a very easy to use application for Windows. After downloading it, all you have to do is click on "Open File" and select the .dat file you wish to use. In this way, on the left side of the window the program will show you the text contained in the selected .dat file and on the right side the documents it contains.

TNEF's Enough

This is a program for Mac that allows you to extract any data contained in .dat files generated by Microsoft Outlook. Once downloaded from your app store, you will find it in the Applications folder of your device. Once you open it, click on the "File" button at the top left of the menu bar and then click on "Open". Then indicate the location where the .dat document to be opened is located. When you are done, extract all the elements from the selected .dat file using the "Export all" option from the TNEF's Enough File menu.

It is not always necessary to install a program on your computer to open a .dat file. To do this online, and therefore rather quickly, you can in fact connect to Once on the portal, upload the document by clicking on the "Upload file" button and then click on "Start". The result will be automatically converted into the correct document, whether it is a Word file, PDF, Excel, etc.


To solve the problem upstream, you can finally start with the choice of email client. This is the case of Thunderbird, which contains many extensions that can extend its functionality. One of them, "lookout", for example, allows you to read and decode attachments in .dat format. To do this, start the program, click on the ≡ button at the top right corner and select "Add-ons". In the window that opens, select the "Explore" item, type "lookout" in the search bar and press Enter. After installing it, simply open an email that contains the .dat file and Thunderbird will show you the real content of the file in the preview.