DAT File

What are DAT files and how to open them

Are you having problems opening a DAT file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your files.

What is a DAT file?

DAT files have multiple uses, and Outlook Email in Rich Text Format (winmail.dat) is one of them. Read more about the other uses further down the page.

Outlook Email in Rich Text Format (winmail.dat)

Sometimes you may receive an email attachment named winmail.dat and wonder what that is. You see it because the sender of the message used the Microsoft Outlook email client and sent the email in Rich Text Format, a format that allows different font sizes and colors.

Not all email clients understand this format, and in this case, the Rich Text formatted email message ends up as a winmail.dat file attached to the email.

Technically these files are called TNEF files, short for Transport Neutral Encapsulation Format, which is the name Microsoft used for the file format.

There are various stand-alone viewers available if your email client does not support winmail.dat files.

How to open DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

Programs that open Outlook Email in Rich Text Format (winmail.dat) files

Last updated: January 22, 2023

All known file formats using extension .DAT

While Outlook Email in Rich Text Format (winmail.dat) is a popular type of DAT-file, we know of 54 different uses of the .DAT file extension. Different software may use files with the same extension for different types of data.

Windows Registry Hive

Microsoft Windows uses a concept called the Windows Registry to store various configuration settings that affect how Windows and installed software works. The registry values are stored in different registry files, called Registry Hives. For example, the Registry holds information about which application you have selected to be the default opener for JPEG images.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Bitcoin data

The original Bitcoin client stores private key information in a file named wallet.dat. This file contains your private keys, public keys, the transactions related to your wallet, and other important data. If you have an HD wallet, it also includes the HD seed and the private key's derivation paths. Keep this file safe, as it contains your bitcoins.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

LabVIEW Binary Data Log

LabVIEW provides an easy-to-use application development environment designed specifically for the needs of engineers and scientists. Without any prior programming experience, you can use LabVIEW to take measurements from various devices and create custom software functionality.

Data captured by your application can be logged to files in various formats using built-in functions. The DAT format is more compact than a user-readable text format and can contain various data, e.g., temperature readings.

DAT opener for Windows

We have identified one DAT opener that is compatible with this specific type of DAT file.

Surface-water Modeling System Dataset

Surface-water Modeling System (SMS) Software is a solution for building and simulating surface water models. It is a graphical user interface and analysis tool that allows engineers and scientists to visualize, manipulate, analyze, and understand data. Build a conceptual model in SMS by constructing a high-level representation of the model using familiar GIS objects: points, arcs, and polygons. The data file contains these objects.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

MicroStation Resource data

MicroStation is a Computer-Aided Design (CAD) software used in the architectural and engineering industries to design structures and products in 2D and 3D. A resource is an element that can be used in such a drawing project.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

Clarion 2 Database

This file contains the data users have entered into a program developed in the Clarion programming language. Clarion is a development environment focused on creating database applications. Therefore, the database file is not used by Clarion itself, but one of the hundreds of programs developed using this programming language. Some viewers can display the content of any Clarion generated database, as the database format itself is standardized.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Runtime Software Compressed Disk Image

DriveImage from Runtime Software is used to create copies of an entire hard drive partition. A drive copy is saved as an XML file accompanied by a DAT file, and optionally a series of files named 001, 002, 003, etc., if you have selected to split the copy into multiple files of smaller size.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

CHEMICAL Molecule Data

CHEMICAL is a molecular modeling program for MS-DOS by Larry Puhl that bonds and places atoms that the user has selected from a Periodic Table. Its associated data files contain molecular data models.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Adobe Freehand Project

Freehand was a vector drawing program for Windows and Mac from Adobe, which acquired it from Macromedia. At the time, it was a market leader in vector drawing programs. The DAT file created by this program was a vector drawing project file.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Allegro Game Engine data

Data file for games developed using the Allegro Game Engine. The files can contain graphics and sound elements.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Clrmamepro DAT / MAME Listinfo ROM info

This type of dat file contains information about an arcade machine ROM copy. The files contain, e.g., name of the game, manufacturer, size, checksums etc. The checksums can be used to verify that your copy of the ROM is complete and unaltered.

MAME is a Multi Arcade Machine Emulator that can run old arcade games on your computer.

Programs that open these DAT files

We have identified 2 DAT openers that are compatible with this specific type of DAT file.

DirTel Database

DirTel is an address book for MS-DOS, and the associated DAT file contains the addresses entered by the user.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

PasswordBox Encrypted Database

PasswordBox is a console-mode program that will keep all your passwords safe in an encrypted database protected by a master password. The database consists of a single .dat file.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

DVD Master Disc Control File

DDVID.DAT is one of several control files written to the area reserved for mastering content on a Master DVD to prepare pressing duplicates.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

GeoLite1 IP geolocation database

GeoLocation database from Maxmind. It contains mappings between IP-addresses and physical locations, so you can use a user's IP address to look up the user's country. Home pages often use it to enable specific behavior when a website visitor is from a specific country - e.g. block access, change language, or change currency.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

InnoSetup Uninstall Log

InnoSetup is a Windows installation program used by developers to create installation packages of their software. The uninstall log files contain information about which files must be removed if you decide to uninstall a software program.

You usually do not need to edit or view these files, as they only contain information usable by the software program that uses them.

CardFile PIM data

Data file for the legacy Personal Information Manager software, CardFile PIM, for the Atari home computers.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

EasyRecovery saved recovery state

EasyRecovery from OnTrack is a software tool to recover data from crashed hard drives and solid-state disks. During the recovery process, it saves a state file so it knows which sections of the drive have been processed so far.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

Linux Kernel X86 Bootable

A Linux kernel is the "brain" of a Linux system. It is the main Linux operating system file that provides the low-level functions of the operating system.

You usually do not need to edit or view these files, as they only contain information usable by the software program that uses them.

LocoScript Data

LocoScript was a word processor first developed for the Amstrad CPC 464 home computer in the late 1980s. Later, versions were made for MS-DOS. Documents saved by LocoScript used the .dat file extension.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

Microsoft Internet Explorer cache

The Internet Explorer web browser stores certain data on your PC to speed up the display of web pages. For example, if you revisit the same page, the web browser will only need to download the changed content and not, e.g., fonts and images that have not changed. This saves both bandwidth and time.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

MirandaIM database

Miranda IM was an instant messenger application for Windows with support for multiple messaging protocols. You could chat on ICQ, IRC, AOL, and many other platforms using this single application.

The database file contains the log/history of all your chats.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

Palm Desktop DateBook

Calendar database file used by Palm desktop software, a companion software for Palm Pilot handheld devices. This file contains a user's calendar entries and repeating events.

Programs that open these DAT files

We have identified one DAT opener that is compatible with this specific type of DAT file.

StarForce protected data

StarForce is a copy protection system. It stores one or more files in a single "container" that gets protected by their proprietary system. Software developers embed part of the StarForce protection into their application, enabling it to read the data from the protected container file if the user has entered the correct license key. Without the key, the protected data cannot be read.

You usually do not need to edit or view these files, as they only contain information usable by the software program that uses them.

VideoCD MPEG

MPEG encoded video stream in a RIFF container used in VideoCDs.

Programs that open these DAT files

We have identified 2 DAT openers that are compatible with this specific type of DAT file.

Windows boot log data

When a Windows PC starts (boots), Windows will log data about the boot process to a log file. This file will help resolve startup problems as the administrator will be able to see how far in the startup process Windows came before a problem occurred.

We have not yet verified any programs for Windows that work with this specific file format. If you know one, please use the 'Suggest a program' link below. Thanks!

More file formats using the DAT extension

Through our research of DAT files, we know that the following formats exist. However, we have not yet analyzed them in detail.

Help us help others

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