What exactly do you mean by “when I open any header file”? Local testing has not been able to reproduce the reported behavior, so having a sample setup / repro case from those expericing the issue will help uncover the cause. For reference, here are the steps I tried:
- Create new project
- File->New C++ Class → Actor class
- In MyActor.h, add
#include "Engine.h"above#include "MyActor.generated.h" - Compile
Following this the project compiled successfully with no errors. If you are doing something differently, please let me know.