Error Script, Not found class GameObject

Hello…

Recently installed Unity on my PC (Windows 10), I have something that I find very odd, is that from one moment to another, open the Monodevelop and I mark error in a simple statement as

public GameObject referencesGO;

It’s like GameObject not find the class. Besides not find Camera.main, Vector2 among other classes and do not understand why. Brand error in almost everything.

Thank you very much, I hope someone has the solution to this problem because it does not allow me to program anything.

There are two possibilities:

  • You removed the line using UnityEngine; at the top of your script
  • You opened the script file alone inside MonoDevelop. When you open a script inside Unity, Unity will open the solution / project instead of just a single file.