To this date (4/21/16), the problem has still not been resolved. I use gmail, so I downloaded the Chrome browser, and with Chrome, I had no problems attaching files to my emails. I guess I won't be using Microsoft Edge anymore. Also, it's pretty hard to believe that Microsoft would've ever released this software, without having found such a major bug like this.
It's actually quite funny....I watch the shopping channel, QVC, where they frequently sell laptop computers. All the reps are always pushing all the "wonders" of the new browser, Microsoft Edge.....how you can "highlight" and even write on web pages, and send them to friends.....but it cannot even perform the majorly fundamental task of attaching files to email. So ironic! Everyone is clearly asleep at the wheel!