Worked for my Excel Spreadsheets
Thank you for providing this public service for free. It made my life so much easier. For people who can't figure out how to use the app: Go into your email, and attempt to open the winmail.dat file from your email. An option should be available to open it in TNEF's enough. That will pull the files into the app, where you can view their actual extension types, and save them as their actual file type.