Frustrated by winmail.dat files? Letter Opener saves the day!

Anyone who has owned a Mac has run into them — those mysterious winmail.dat files. You try double-clicking on those files and nothing happens, leaving you to wonder what someone from the world of Windows was trying to send you. Fortunately, there is a solution available in the form of Letter Opener for macOS, macOS Mail and iOS (free trial for macOS and iOS with in-app premium purchases).

What are winmail.dat or MSG files? They’re email messages from Microsoft Outlook that cannot be read natively by Macs. Mac users also occasionally receive XPS files, which are Windows document files that need to be converted to PDF format before they’re readable. Particularly if you’re a Mac user in an all-Windows environment, those winmail.dat, MSG and XPS files can be frustrating.

How easy is Letter Opener to use? On iOS devices, just tap and hold on the winmail.dat file, then select “Copy to Letter Opener” to open the file. With Letter Opener for macOS Mail, the winmail.dat files are converted automatically without any intervention on your part. Letter Opener for macOS opens those winmail.dat files regardless of what mail app you’re using — Spark, macOS Mail, Airmail, and even Outlook — with a simple drag and drop.


Letter Opener Version 9 for macOS Mail is $39.99, with upgrades from earlier versions available for just $19.99. If you’d like to try Letter Opener either for macOS or iOS, download them from the iOS or Mac App Stores for free and try all of the features for 14 days, then decide which premium in-app purchase is right for you. 

Letter Opener has been the go-to solution for Mac owners frustrated with winmail.dat files for over ten years. We are proud to count Letter Opener as this week's sponsor of the Apple World Today.