If I start a new file, enable sky , put on preview rendering( shift-Z) and then maximize the viewport (shift-space) blender crashes
rpr 1.7.212
macos 10.13.6
blender 2.79b
tested both on internal 560 pro and external vega 64
I have not attached file since it can be replicated by opening a new file and enabling the sky feature and following the above steps