Have you upgraded to windows 10 and noticed that your middle button no longer is activating big picture? Awfully frustrating! I’ve not actually found a guide online to fix this. But I’m here to show you how, it’s a simple 2 step process.
That’s it! Once you’ve done this your Big Picture will work. If you ever want this back (for some reason) you can still reach it with Windows Key + G. Happy gaming!