Unity 3d on build screen goes to black

Recently I updated one of my projects - http://bit.ly/solarsystemunity3d to Unity 2019.1.6f1 and when I run it in unity editor everything was working as expected, however when I build it for desktop and run I got black screen. I could not find solution online even tough I tried all tricks and tips I found. For instance setting Clear Flags on on all camera to Don't clear, reducing texture resolution.
After playing around and scratching my head I realised that I made all cameras into prefabs in my previous version of unity, when I right clicked in project hierarchy window and selected Unpack Prefab Completely it magically started to work again as expected.
Hope that helps someone out there ans save a lot of time.