Chiming in here, as I had this problem and nothing in this thread was helpful. Evernote was "somewhere" off screen. I could see it via the task bar, Alt-Tab, and the Task View, but nothing would bring it onto my monitors. Win+Arrows did not help. Killing the app and reopening it did not help. Disconnecting all my extra monitors did not help. Flipping Window Snap settings did not help. The only way I was able to get the app to come back was to use Win+ArrowRight to snap a DIFFERENT app on my main monitor. When Windows presented the UI to select a 2nd window to snap left, I chose Evernote and it finally came back. Wonder of wonders, now that I've found the black magic required to get it to behave correctly, it seems to respect the Win+Arrow keys again.
Anecdotally, I know the Evernote team has been on this journey to rearchitect their code base over the last couple years and all that, but man, this application still has odd and frustrating behavior like this that NO OTHER APPLICATION on my machine exhibits. It's fishy, and smells to me like the application is not conforming to some Windows development standards that virtually all other applications conform to.
For a tool that is centered on productivity, it is sometimes very unproductive to use. Instead of adding a quick recipe like I intended, I instead had to spend my time trolling forums and trying to get it to simply be useable. This is a very poor user experience.