Why is this version working like that?

So i was using 4.15 and everything was working fine…
Then i decided to change to 4.16… all my game crashed and impossible to recover but it’s okay it was just a test.

My problem right now is that i cant code in 4.16 since visual studio don’t understand my code!!!

An ex:
tried to write
but the IntelliSense doesn’t give me anything because engine.h isn’t included!
instead they have something new minimal.h something… and that isn’t working. i created the class thru the unreal engine add component and did everything write but it doesn’t work untill i add “engine.h”

Wheni add that it works, you must be thinking “Then why don’t you add that on your cpp file?” well i would do that if didn’t take alot of time doing that for each cpp file am using… it would take insanely long time and still it doesn’t work as fine as in 4.15.3.
I have a great pc, high end pc 2000 dollars + with great processor and everything in the specs and still it takes time… i just want it to run like in the ´version 4.15