THE FILE FIELD GUIDE

.dat

Generic DAT Data

Generic / Ambiguous Data

DAT is not one standard. Different applications use it for settings, game data, caches or attachments. Identify the producer rather than assuming a universal viewer or converter.

What it is used for: Application-specific data with no universal structure
What the file contains: Producer-dependent

All sections, questions and sources

Content reviewed：2026-10-19 · Editor：Kai

Identify DAT by origin and context

Identify DAT by origin and context
Situation / goal	Next action	What to check
Email attachment named winmail.dat	Ask the sender to resend the required document or image as an ordinary attachment.	Check that the actual intended attachment arrives and opens.
A game or application data folder	Record the application, version and companion files; follow its loading or recovery workflow.	Verify records, progress or settings in the original application.
Unknown origin	Ask the sender or producer and retain the original unchanged.	Choose a converter only after identifying the underlying format.

Source for these steps：Microsoft · Exchange: TNEF conversion options

Opening steps

Choose your environment or purpose to see its steps.

Identify purpose from provenance

DAT alone does not identify the format.

Record source, location, same-name companions and timestamps.
Consult producer/application instructions to identify data, settings, attachments or game use.
Retain the original and select a suitable application for a copy after identification.

Inspect a copy

Distinguish inspection from execution.

For identified text data, inspect a copy in an editor.
For binary data use the producer or an appropriate inspection tool.
Identify companions and use the supported workflow rather than renaming or overwriting.

Export data for its intended use

Identify the format before conversion.

Check that the producing app can read the intended content.
Choose its supported export for images, video, tables or settings.
Reload and compare counts, values or appearance and retain source/companions.

Menu labels and support vary by app, OS and version. Preserve the original before making changes.

Recover the intended attachment from a winmail.dat delivery

Outlook/Exchange TNEF messages can encapsulate formatting and original attachments in winmail.dat. This does not mean that every DAT is TNEF.

Tell the sender that only winmail.dat appears and name the attachment you need. The sender or administrator can check message settings; renaming DAT to PDF or MP4 will not extract it.

Source for these steps：Microsoft · Exchange: TNEF conversion options / Microsoft · Content conversion

Troubleshooting by symptom

Unreadable text can simply be binary data. Re-saving a misinterpreted file can damage it.
A video-like name does not establish a video format. Mail-related DAT and game/business DAT must be identified separately.
Mail DAT mistaken for video: identify the producer and original content with the sender.
Unreadable editor display: identify binary data versus text encoding.
Renaming fails: structure is unchanged; investigate the purpose using an original-name copy.

Identify the DAT producer before conversion

Identify producer/internal format; ask the sender for the application and intended format if unknown.
Use its documented export to create a copy in the intended format.
Identify producer/format and compare actual supported export; distinguish this from changing the DAT suffix.

Renaming to MP4/CSV/TXT is not conversion. Avoid sending confidential data to purported universal DAT converters.

Location and companions provide clues

DAT is a generic suffix; investigate source and neighboring files rather than applying one loader to games, settings and attachments.

Separate guesses from identification and prefer the producer’s storage documentation over filename assumptions.

Source for these steps：Microsoft · Common file name extensions in Windows

What to check before conversion

Unknown data cannot be reliably converted merely by choosing MP4 or CSV; confirm readable content in its source application.

Conversion may omit information; compare content, counts and companions and separate verified output from source.

Source for these steps：Microsoft · Common file name extensions in Windows

Related-format differences

Related-format differences
Format	Main role	What to check
DAT	Generic data suffix	Identify format by producer
BIN	Generic binary suffix	Not necessarily the same format
TXT / CSV	Purpose-specific output	Requires supported export

Handling and security

If producer/content are unknown, avoid execution or overwriting and determine whether it is important app data.

Questions and answers

Is there one universal DAT viewer?

No single format exists; the required tool depends on its producer.

Can I delete DAT?

It may be required application data. Identify and back it up before deciding.

Can DAT be converted to MP4?

It depends on the contents. Use a suitable media export only after identifying actual video data.

Should I give a converter my email password?

Do not give a third-party converter your mail password. First ask the sender to resend the intended attachment normally.

Format facts: name, steward and MIME type

Formal name: Application-specific data (not one universal format)
Steward / specification: Depends on the application
MIME type: No unique MIME type; depends on the producer

Primary and official sources

Platform documentationCommon file name extensions in Windows
Documents showing suffixes and distinguishes renaming from conversion.
Microsoft · Link checked：2026-10-12
Software documentationExchange: TNEF conversion options
Explains TNEF attachments and sender-side message settings.
Microsoft · Link checked：2026-10-19
Software documentationContent conversion
Explains how original attachments and message properties may be encapsulated.
Microsoft · Link checked：2026-10-19