I have never written a review for an app, but I am so impressed with Winmail.Dat Viewer Pro, I had to give it the kudos it deserves. I received a win mail.dat file attached to an email. It showed up out of the blue and I had no idea how to open it. After doing research to find out what a win mail.dat file was, I went to the App Store to find help. There were several apps with good customer ratings, but I chose to pay $1.99 for WINMAIL DAT VIEWER PRO app without ads. It downloaded quickly and I was able to use it immediately. I did not have to create an account before using the app. I opened Winmail Dat Viewer and a small popup box appeared with instructions to drag the win mail.dat file to the box. I saved the win mail.file from the email to my desktop and then drug it to the popup box. The win mail.dat file instantly converted to a PDF file!! I highly recommend this app. It does exactly what it says it is supposed to do.