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How to open winmail.dat on mac

how to open winmail.dat on mac

Ever stumbled upon a mysterious winmail.dat file attached to an email on your Mac and found yourself scratching your head over how to open it? You’re not alone. These files are typically generated by Microsoft Outlook when the email sender uses the Rich Text Format for their message. Since Mac’s default mail client doesn’t recognize this format, the content gets wrapped into a winmail.dat file. Fear not, for opening a winmail.dat file on a Mac isn’t as daunting as it seems. In this how-to guide, I’ll share the methods I’ve personally used and found effective.


Common Scenarios:

Unexpected Attachments 😯

  • Receiving an important email from a client or colleague using Outlook and discovering a winmail.dat attachment instead of the expected document.
  • Frustration arises when the Mac Mail app does not provide any clues on how to access the content within the winmail.dat file.

Collaboration Hurdles 🛰

  • Collaborating on a project where different team members use a mix of email clients, leading to compatibility issues and inaccessible attachments in the form of winmail.dat files.
  • The urgency to access the information locked in a winmail.dat file for project continuity.

Lost in Translation 💬

  • Facing repeated communication barriers when interchanging emails with parties embedded in a Microsoft Outlook environment.
  • The need for a reliable way to open and convert winmail.dat files for seamless communication and data transfer.

Step-by-Step Guide. How To Open Winmail.dat On Mac:

Method 1: Use the TNEF’s Enough App 🖥

  • Download and install TNEF’s Enough, a free utility designed specifically for Mac users to open winmail.dat files. Head over to the Josh Jacob’s website to get it.
  • Launch TNEF’s Enough and use it to open the winmail.dat file either by dragging and dropping it onto the app window or by using the ‘Open’ option within the app.
  • Explore the contents and extract the necessary files onto your Mac.

Note: TNEF’s Enough provides a simple interface but may not work with all variations of winmail.dat files.

Conclusion: This method offers a straightforward solution for Mac users to access the contents of winmail.dat files without much hassle.

Method 2: Online Converters 💾

  • Find a trustworthy online winmail.dat converter. One such service is Winmaildat.com.
  • Upload the winmail.dat file to the converter using the upload option on the site.
  • Wait for the conversion to complete and then download the unpacked files.

Note: Be cautious with sensitive information as you’re uploading files to an external server.

Conclusion: Online converters can be a quick and easy method, especially when software downloads are not preferred or allowed.

Method 3: Dedicated Mac Apps 📘

  • Search for a winmail.dat opener app on the Mac App Store, like Letter Opener.
  • Download and install the chosen app, which typically integrates with the Mac Mail app and automatically opens winmail.dat files in the future.
  • Simply double-click the winmail.dat file within your email, and the app should take care of the rest.

Note: This could be a paid solution depending on the app you choose.

Conclusion: A Mac App Store solution offers simplicity and integration, making it a seamless experience.

Method 4: Use Microsoft Outlook 📨

  • If you have Microsoft Outlook installed on your Mac, you can use it to open the winmail.dat files by re-sending the email to yourself through Outlook.
  • Outlook should interpret the winmail.dat file correctly and display the contents.

Note: This method assumes you have an Office 365 subscription or Outlook installed.

Conclusion: Utilizing Outlook on your Mac is an efficient way to handle winmail.dat files if you’re already embedded in the Microsoft ecosystem.

Method 5: Using Terminal Commands 💻

  • Advanced users can make use of macOS’s built-in Terminal to extract the contents by installing a command-line tool called ytnef.
  • First, install Homebrew if you haven’t already, by executing ‘/bin/bash -c “$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)”‘ in Terminal.
  • After installing Homebrew, use the command ‘brew install ytnef’ to install the ytnef tool.
  • Then run ‘ytnef –verbose –save –folder . ~/path/to/winmail.dat’ to extract the files.

Note: This method is for users comfortable with command-line operations and might require additional steps depending on system configurations.

Conclusion: Terminal commands offer a free and powerful way to handle winmail.dat files for those who prefer a command-line approach.


Precautions and Tips:

Safe Handling of Files 🧳

  • When using online converters, ensure that the service is reputable and consider the privacy policy before uploading sensitive documents.
  • Always scan extracted files for viruses or malware using a reliable antivirus software to protect your Mac from potential threats.

Integration and Compatibility 🖥

  • If you regularly receive winmail.dat files, explore apps that integrate with your email client for seamless file opening.
  • Check compatibility of the apps or tools with the version of macOS you are using to avoid any software conflicts.

Additional Insights

When working in a cross-platform environment, it’s common to encounter file compatibility issues. The winmail.dat dilemma is just one example of how different email clients handle rich text and attachments. To minimize these issues, it’s essential to maintain open communication with your correspondents about preferred file formats and sending methods.

The preference for plain text over rich text in business correspondence could help circumvent the creation of winmail.dat files altogether. Additionally, educating colleagues on how to adjust the settings in Microsoft Outlook to send emails in formats universally understood will promote smoother collaboration.

For those handling sensitive data, consider data encryption and secure transfer methods instead of relying on email attachments. This practice not only secures your information but also avoids the winmail.dat confusion since the attachments are handled via secure external means.

Finally, it’s worth exploring email client options that offer better compatibility across different platforms. Migrating to an email service known for its versatility could provide long-term benefits in a multi-platform workspace. For more insights into file compatibility and data sharing, you might want to look into resources provided by the Internet Engineering Task Force (IETF) or visits Apple’s official support page for updated information on macOS capabilities.


In conclusion, while winmail.dat files might look unwelcoming at first glance on a Mac, a variety of solutions exist to conquer them. Whether opting for a software download, such as TNEF’s Enough, relying on online converters, exploring integrated Mac App solutions, utilizing Microsoft Outlook, or delving into Terminal commands, each method has its merits and caters to different user needs and technical comfort levels.

Always remember to prioritize security when dealing with email attachments and maintain software updated for the best compatibility and user experience. By following these insights and tips, you’ll ensure that winmail.dat files won’t disrupt your workflow or business communications again.


The simplest way is to use the native macOS Preview application. Right-click the winmail.dat file, select ‘Open With’ > ‘Preview’. If this doesn’t work, you might need a third-party app.

No, the default Mail app on macOS cannot natively open winmail.dat files. You’ll typically need a dedicated tool or conversion utility.

A third-party application like TNEF’s Enough can decode and open the contents of winmail.dat files, allowing you to access the inaccessible attachments. TNEF’s Enough provides this functionality.

Yes, you can use an online service like Winmaildat.com to upload your file and preview its contents. This saves you from needing to install anything. Visit Winmaildat.com for this service.

First, download and install TNEF’s Enough. Then, drag the winmail.dat file into the app’s window, and it will display the contents, allowing you to extract the files.

Currently, there are no known mail client plugins that directly open winmail.dat files in the macOS Mail app. Using a stand-alone application or online service is necessary.

Make sure you are using an updated version of the third-party tool. If it still won’t open, the file might be corrupted or you may need to try a different tool.

Without software, the best alternative is to use an online converter like Winmaildat.com, which can convert winmail.dat files into more accessible formats.

Winmail.dat files can include various types of attachments like documents, images, and calendar invites which are formatted in Microsoft’s TNEF encoding.

As with any email attachment, there’s a risk of malware. Always ensure that you trust the sender and consider scanning the file with antivirus software before opening.