How to Open a DAT File on Windows, Mac, or Linux

What a DAT file is and why you can't just double-click it

A DAT file is a generic data container — it holds information in a format specific to whatever program created it, but Windows, Mac, and Linux have no built-in way to know what that program was. Double-clicking a DAT file usually produces an error or opens it in Notepad as unreadable text. The file extension tells you almost nothing about what's inside.

The real problem is that DAT files come from dozens of different sources: video players, email clients, installation programs, games, backup tools, and proprietary software. A DAT file from VirtualDub looks nothing like a DAT file from Kazaa or from a Canon camera. You need to know the source to open it correctly.

The good news is that most DAT files fall into a handful of common categories, and each has a straightforward solution. The bad news is that you may need to try more than one approach to find out which category yours belongs to.

Key Takeaways

DAT files have no standard format — the program that created the file is the only one that can reliably open it, so identifying the source is your first step.
Video DAT files from cameras or camcorders usually open in VLC media player or the manufacturer's software without renaming.
Email client DAT files (Outlook, Windows Mail) require the original program or a specialized converter to read the contents.
If you don't know the source, try opening the file in a text editor first — if you see readable text or recognizable patterns, you can narrow down what created it.
Renaming a DAT file to a more common extension (like .avi, .mpg, or .txt) sometimes works if you already know what type of data it contains.

Identify where the DAT file came from

Before you try to open anything, figure out the source. Check the folder where the file sits — the surrounding files often give clues. A DAT file in a camera's DCIM folder is almost certainly video. A DAT file in an Outlook backup folder is almost certainly an email database. A DAT file in a game directory is game data.

If the file came with software you installed, search your computer for the program's name and open it — it may have a File menu or Import option that can read DAT files. If the file arrived in an email or download, ask the sender what program created it.

If you have no idea, right-click the file, select Properties (Windows) or Get Info (Mac), and look at the creation date and file size. A 50 MB DAT file is probably video or audio. A 2 KB DAT file is probably text or configuration data. This won't tell you the exact source, but it narrows the field.

Open video or camera DAT files

DAT files from digital cameras, camcorders, and some video editing software are usually video files with the wrong extension. Try opening them in VLC media player, which is free and handles dozens of video formats. Download VLC from videolan.org, install it, then right-click the DAT file, select "Open with", and choose VLC.

If VLC doesn't work, the file may need its extension changed. Right-click the file, select Rename, and change the .dat extension to .avi, .mpg, .mov, or .m2ts — try each one and open with VLC after each rename. If one of these works, you've found the real format. If none work, the file is probably not video.

For camera-specific DAT files, check the manufacturer's website. Canon, Sony, Panasonic, and other camera makers sometimes provide software that reads their proprietary DAT formats. Download the software, install it, and open the file through the program's menu rather than by double-clicking.

Open email and backup DAT files

Outlook, Windows Mail, and some other email clients store messages in DAT format. If you have the original program installed on the same computer, open it and look for an Import or Open option in the File menu. The program should be able to read its own DAT files.

If you don't have the original program, or if it won't open the file, you need a converter. Search online for the specific program name plus "DAT converter" — for example, "Outlook DAT converter" or "Windows Mail DAT converter". Several free and paid tools exist for each major email client. Download one, follow its instructions to select your DAT file, and it will usually export the contents to a standard format like .pst, .eml, or .csv that you can open in any email program.

Be cautious with online converters that ask you to upload the file — use desktop software instead if the DAT file contains private information.

Open text and configuration DAT files

Some DAT files are actually text or configuration data stored with a generic extension. Open the file in a plain text editor — Notepad on Windows, TextEdit on Mac, or gedit on Linux. If you see readable text, words, or recognizable patterns, the file is text-based and you can read it this way.

If the text editor shows gibberish or binary data, the file is not text. Close it and try a different approach. If the text editor shows readable content but it's formatted strangely or contains code you don't recognize, the file may be configuration data for a specific program — search online for the program name and "DAT file" to learn how to interpret it.

Rename the file if you know its real type

If you've determined that the DAT file is actually video, audio, or another standard format, renaming the extension often works. Right-click the file, select Rename, and change .dat to the correct extension. Common conversions include:

.dat to .avi for video files
.dat to .mpg for MPEG video
.dat to .mov for QuickTime video
.dat to .mp3 for audio files
.dat to .txt for text files

After renaming, try opening the file with the program you'd normally use for that format. If it opens and plays or displays correctly, the rename worked. If it doesn't, rename it back to .dat and try a different extension.

Renaming only changes the label — it doesn't convert the actual data. This works only when the file's contents match a standard format but were labeled with the wrong extension.

Use online file analysis if you're stuck

If none of the above steps work, upload the file to an online file analyzer like FileInfo.com or TrID.net. These tools examine the file's internal structure and often identify what created it, even if the extension is wrong. They show you the file type and sometimes suggest which programs can open it.

For privacy-sensitive files, download and run TrID as a desktop program instead of uploading to a website. TrID is free and works offline on Windows, Mac, and Linux.

Frequently Asked Questions

Can I just change .dat to .txt and open it in Notepad?

Only if the file actually contains text. Changing the extension doesn't change what's inside the file — it just changes the label. If the file is binary video or audio data, renaming it to .txt won't make it readable in Notepad. Try opening it in Notepad first to see if it contains text; if it shows gibberish, the file is not text-based.

What if the program that created the DAT file is no longer installed?

For video and audio files, VLC or another media player often works without the original program. For email and backup files, search online for a converter tool specific to that program — most email clients have third-party tools that can read their DAT format. For other types, try a file analyzer like TrID to identify the format, then find a program that supports it.

Is it safe to download a DAT file converter from the internet?

Download converters only from the official website of the software company or from well-known sources like GitHub or SourceForge. Avoid random websites offering converters, as they may contain malware. For email and backup files containing sensitive information, use desktop software rather than online converters that require uploading.

Why do some programs use DAT as a file extension?

DAT is a generic label that means "data file" — it tells you nothing about the format. Older software and proprietary programs often used it because it was simple and didn't require a specific extension. Modern software usually gives files more descriptive extensions like .mp4, .pst, or .json so programs can identify them automatically.

Can I open a DAT file on my phone?

It depends on what the file contains. If it's video from a camera, you can usually transfer it to your phone and open it in a video player after renaming the extension to .avi or .mp4. If it's an email backup or proprietary format, you'll need an app designed for that specific type — search your phone's app store for the program name plus "viewer" or "converter".

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.