Literally, everything in scene/level floats up and away. When i load any project, once fully loaded, everything floats up into the sky. I can select an object and press F to bring back into view but it floats away immediately.

ANY help with this would be great.

Useful troubleshooting details:

OSX 10.12.4
UE4.15.1

I purchased and installed the Side Scroller Shooter Kit on Thursday. This started today after closing and reopening the engine.
I also installed the Xbox controller "software" (to computer) in order to use a gamepad with computer/game. This: https://github.com/360Controller/360Controller/releases



*** EDIT = Well, not sure what I did/happened but after quitting everything and restarting, I can once again open things without issue...
I did unplug the Xbox One controller.