This afternoon I added another sprite to my 2D game and this time when I hit Play the sprite vanished. Turns out the Sprite Renderer > Material is being changed to None (even if I save the scene before hitting Play).
If I manually change the Material back to Sprite - Default then everything is back to normal and it works fine when I hit Play.
What’s (especially) odd is that previously today dragging sprites into the game worked just fine – I don’t recall doing anything “weird” that made the problem crop up.
Jay
PS - Using 5.4.0b17 on Mac, and quitting and restarting Unity didn’t fix the problem. Only manually resetting the Material fixes it.