According to the new rules, put into effect on March 29, “Apps that emulate a game system are not allowed on any device family.”
While it’s more than a little annoying that Windows is closing its doors officially to such innocuous software, it’s understandable why it would from a business standpoint. After all, if you’re emulating a console Microsoft doesn’t own, it might be legally thorny to allow you to sell said emulator on its store.
Notably, the DOSbox emulator app for Windows phone is still available on the Store at the time of this writing. There might be some wiggle room for apps that don’t specifically emulate a game system. Also, anyone who downloads their emulators from elsewhere on the internet won’t notice much of a difference.
The most noticeable absence following this rule change is the Universal Emulator app, which let you play Nintendo and Sega classics on Windows 10 computers and tablets, as well as Xbox One. Developer NESBOX lamented the setback, though it still has a browser-based version available.
— NESBOX (@nesboxcom) April 4, 2017
Obviously anyone can still download emulators from elsewhere on the internet, as well as the Google Play store. This new ban does mean, however, that using game-based emulators is even more clandestine than before.