Opening a DAT file on a Mac can feel confusing because the extension doesn’t reveal what type of data it holds. These files are generic containers that may include text, images, video, or email formatting information. The simplest way to open a DAT file on Mac is to right-click it, choose “Open With,” and select TextEdit or another suggested app.
Many DAT files appear as email attachments, often named winmail.dat. This happens when email programs like Outlook send data in a format that Apple Mail can’t interpret. In these cases, the file may just contain the original message or attachments that need a dedicated viewer or an online tool to extract.
If the file isn’t text-based, it may open in apps like Preview, VLC, or QuickTime depending on its contents. Changing the file extension to match the actual data type, such as .txt or .mp4, can also work. With the right method, anyone can handle DAT files on a Mac without guesswork.
How to Open DAT Files on Mac (Complete Guide)
DAT files can be confusing because “.dat” isn’t a single file type—it’s a generic data container used by many programs. On a Mac, how you open a DAT file depends entirely on what’s inside it and where it came from.
This guide explains how to identify and open DAT files on macOS, step by step.
What Is a DAT File?
A DAT file simply means “data.” It may contain:
- Video or audio data
- Plain text
- Program‑specific information
- Email attachments
- Game or application data
Before opening it, you need to determine what kind of data it holds.
Step 1: Identify the DAT File Type
Check Where the File Came From
- Email attachment → Often a video, document, or encoded file
- VCD or DVD rip → Usually video
- App or game folder → Likely program data (not meant to be opened)
- Exported data file → Possibly text or spreadsheet data
Preview the File
- Right‑click the DAT file
- Select Quick Look
- See if macOS can preview it
If nothing appears, move on to the next steps.
Method 1: Open DAT Files as Video (Most Common)
Many DAT files are actually video files, especially from older media formats.
Try VLC Media Player
VLC is the most reliable option.
- Download VLC Media Player for macOS
- Open VLC
- Click File → Open File
- Select the DAT file
✅ If it plays, the DAT file is a video.
💡 Tip: You can rename the file from .dat to .mpg and try opening it in QuickTime or VLC.
Method 2: Open DAT Files as Text
Some DAT files contain readable text or configuration data.
Using TextEdit
- Right‑click the DAT file
- Choose Open With → TextEdit
If the file contains readable text, it will display normally.
If it’s mostly symbols, it’s likely binary data and not meant to be read.
Using Terminal (Advanced)
cat filename.dat
Or:
less filename.dat
Method 3: Open DAT Files from Email Attachments (winmail.dat)
If you received a DAT file via email, it may be winmail.dat.
How to Open winmail.dat on Mac
- Use The Unarchiver
- Use Winmail.dat Reader
- Use online winmail.dat extractors
These tools extract the original attachments (PDFs, images, documents).
Method 4: Open DAT Files with the Original App
If the DAT file belongs to a specific program:
- It may only open within that application
- Manually opening it could corrupt the file
Examples:
- Game save files
- App cache or database files
- Software configuration data
✅ In these cases, open the parent app—not the DAT file itself.
Method 5: Change the File Extension (Optional)
Sometimes the file is mislabeled.
Common Extensions to Try
.mpgor.mpeg(video).mp4(video).txt(text)
⚠️ Changing the extension doesn’t convert the file—it only helps macOS recognize it.
Method 6: Use Hex or Binary Viewers (Advanced Users)
For inspection only:
- Hex Fiend
- 0xED
These tools help identify file headers to determine the real format.
What NOT to Do
❌ Don’t randomly edit DAT files
❌ Don’t delete DAT files from app folders
❌ Don’t assume all DAT files are safe to open
Quick Troubleshooting Table
| DAT File Source | Best Way to Open |
|---|---|
| Email attachment | The Unarchiver / Winmail reader |
| Video disc file | VLC Media Player |
| App folder | Open with original app |
| Unknown | Try VLC, then TextEdit |
| Config/data file | Leave unchanged |
Final Thoughts
Opening DAT files on Mac depends on identifying what’s inside. VLC Media Player and TextEdit solve most cases, while email DAT files often require extraction tools. When in doubt, avoid modifying the file until you know its purpose.
Key Takeaways
- DAT files are generic and can hold many types of data.
- TextEdit or a suggested app often opens them on Mac.
- Some files need specialized apps or a quick extension change.
Frequently Asked Questions
Different tools and methods can help open or convert DAT files depending on their contents. Some DAT files hold email data, while others may store video, text, or other information that requires specific programs.
What software can be used to view winmail.dat files on a Mac?
Apps like TNEF’s Enough and Winmail Viewer can open winmail.dat files. These programs are designed to extract attachments and messages that Apple Mail cannot read.
How can I convert a .dat file to a more common file format like .mp4?
If the DAT file contains video, renaming the extension to .mp4 may allow it to play in QuickTime or VLC. If that fails, a video conversion tool such as HandBrake can re-encode the file into a standard format.
Is there a way to open .dat files in Excel on a Mac?
Yes. If the DAT file stores text data separated by commas or tabs, it can be imported into Excel. Open Excel, choose File > Import, and select the DAT file as a text file. The import wizard will guide the formatting.
Are there any online tools available for opening .dat files?
Yes. Websites like winmaildat.com let users upload a DAT file and extract its contents. These services are useful if the file only holds email attachments or formatting data.
Can winmail.dat files be opened on an iPhone?
Yes. Several iOS apps, such as Letter Opener or TNEF’s Enough for iOS, can open winmail.dat files directly on an iPhone. Another option is to forward the email to Gmail, which often displays the attachments correctly.
Is it safe to delete .dat files from my Mac?
It depends on the source. Temporary DAT files from email attachments or downloads can usually be deleted without issue. However, DAT files used by installed software may be required for the program to run, so they should not be removed.
