Unity 5 - Pc freeze

My whole PC freezes in Playmode (increased since 5.3.4), while importing a Project or importing a FBX file.
I couldnt find a Solution or a related Topic. I added my PC specs and the Editor log, maybe someone can help. Thank you very much.

(Filename: Assets/chest.js Line: 410)

NullReferenceException: Object reference not set to an instance of an object

only found this go to your chest java script and look up if a GameObject isnt used ore something. also same in line 97. but i dont know nothing about logs. maybe also try to unchekc error pause in console.
but thats actually nothing to crash about.