If you open your email on a Mac and see that someone has sent you a Winmail.dat file from a PC running Windows, you might not be certain how to open the file on your Mac. Microsoft Outlook saves email messages and attachments in a Winmail.dat file, which is accessible on computers running Windows. Macs don't have native ability to open Winmail.dat files, so you'll need to get a third-party application.
Creative in Austria
Launch your Web browser, navigate to the Creative in Austria website, creativeinaustria.com, and download the LetterOpenerPro application.
Double-click the LetterOpenerPro installer to install it on your Mac. LetterOpenerPro works as a plug-in with Apple's native Mail application.
Click "Mail" on the Dock of your Mac to launch the application.
Click a message containing an attached Winmail.dat file. LetterOpenerPro automatically opens the Winmail.dat file and displays its contents at the bottom of the message window. Click an attached file to open it, or drag the file to a folder on your computer.
Start your Web browser, go to Josh Jacob's website, joshjacob.com/mac-development/tnef.php, and download the TNEF's Enough application.
Double-click the zipped TNEF2's Enough file to expand the app, and then drag the TNEF2's Enough.app application file onto the "Applications" folder in the Dock of your Mac.
Click "Mail" in the Dock of your Mac to launch Apple's native email application. Double-click the email message containing the attached Winmail.dat file. Click the "Save" button at the top of the message to save the Winmail.dat file to your Mac's Downloads folder.
Click "Applications" on the Dock of your Mac, and then click "the TNEF2's Enough" to launch the app. Click "File," "Open," the "Downloads" folder, and then the Winmail.dat file to select it; and then click "Open" to open it.
Click "App Store" on the Dock of your Mac to access Apple's Mac App Store. Type "Klammer" in the search box, and then click "Klammer." Click "Buy," and then type your Apple ID at the prompt to download and install Klammer.
Launch Mail. Double-click a message that has a Winmail.dat file attachment. Click the "Save" button at the top of the message window to save the Winmail.dat file to your Mac's Downloads folder.
Click "Applications" on the Dock of your Mac, and then click "Klammer" to launch the application.
Click "File" from the Klammer menu, and then click "Open," "Downloads," and the Winmail.dat file to open it.