I'm stumped! A friend of mine got 3 emails each with an attached PDF (File1.pdf, File2.pdf, etc..) - all file extensions were ".PDF". When he tried to open them, 2 opened as you'd expect. The third attachment, when double-clicked, popped up a "Save As" dialog - it wouldn't let him view it from the mail app.
Once saved to the local disk, the PDF would open fine. I tried fixing this by installing FoxIt PDF viewer, but the same thing happens - it just opens in FoxIt instead of Edge.
Edited by jhoybs, 22 February 2016 - 04:12 PM.