Developed by Tobias Reinhardt, Winmail.dat Opener is a free app allowing users to open pesky 'winmail.dat' attachments. The free version is fully functional, but if you can not stand the ads, the in-app-purchase will remove ads.
Winmail.dat Opener is available for both Android and iOS users. Since many e-mail clients do not support rich-text message contents and attachments from older versions of Microsoft Outlook applications, people who still use these versions will find Winmail.dat Opener very useful and convenient.
The winmail.dat file contains Rich Text Format information for the message but usually cannot be opened by the normal e-mail clients. Winmail.dat files are in fact called T.N.E.F. files (Transport Neutral Encapsulation Format). Microsoft Outlook e-mail for Windows send e-mails in TNEF format, but most other e-mail clients or applications do not understand TNEF. The app will extract the winmail.dat file on your device, then you can preview, resend or print or save them.
Normally, you just need to open the context menu of the winmail.dat attachment in your email client, then select "Winmail.dat Opener". But if you cannot find "Winmail.dat Opener" in the context menu., you can turn to the second method. By saving the winmail.dat attachment on your phone and starting the "Winmail.dat Opener" app afterward, you can then select the previously saved file successfully.
Please do note that not every file ending with ".dat" is a winmail.dat file. There are also many other file formats which also ends with the .dat extension. Winmail.dat Opener cannot open a file that's not actually winmail.dat file.
