Infamous White Screeen While Preloading

Greetings to all good people of Adobe Community,

Unfortunately using CP5.5 and CP6, white screen while preloading always appears. White screen disappears after a few seconds (or more) and preloader shows 15% progress and continues to load until 100% (or less depending on settings).

I have tried everything: switched preloaders, disabled Quiz reporting, making new course, aggregated project, removing audio, first blank slide, auto start, etc.

No matter what I do there is always that white screen and it is so frustrating since there is a series of big chapters in this course and after user switches to another chapter white screen just hangs in there and they always think something went wrong and they don't wait 5-6 seconds (or more) for preloader to show (again at 12-15% of loaded content). Please see attached video.

I was hoping CP6 won't be having this issue but unfortunately it does. Any suggestion on how to fix this  would be appreciated. Thanks!