problem when compiling VR project

Hello friends, I wanted to discuss a problem I have, I have not been able to find a solution. I have a project that has 8 levels, 1 level with an interactive menu, the 2 level with a 360 video, the 3 level with a space where 5 planets are, each planet is programmed to open a level, independent, at that level it will be an architectural project.

The problem is that the project in total weighs 40GB for being complete architecture projects, I have already passed each level to a new project so that unused assets are eliminated. Followed this generated the executable, but when I open it I get an error like when Unreal stops, but still opens the project, and the first 3 levels perfect, but being on the planet level, and select a planet so that open the project, the application gives an error and closes.

How can i fix this? And is it correct that a project that weighs 40GB, when generating the executable weighs 1GB?