Just installed blender 2.78 on windows 8.1 under parallels. When I start the game engine, the cursor disappears when it enters the blender window. Crtl-alt to release the cursor doesn't help. changing the settings to optimize or not for games doesn't help.
Different problem on blender install directly on the mac (10.12.5). Here, when I start the game engine the blender window just flickers rapidly and becomes entirely unusable.
In both cases everything is fine until the game engine starts.