Just got this error, have created scripts with Visual Studio fine with not issue. But started a new project and got the error

This hasn't been resolved yet

Definitely should be a different error message like "Class Name must be the same as the script filename".

I've already understood why this happened with me. In my case file name of script was different with class name for one letter. I fix mistake and all work good

Yes I have this problem with Unity 2018.1.0f2

with Unity 2018.1.0f2

I'm getting this error with a newly created scripts.

I'm getting this error message on scripts that definitely derive from MonoBehavior that were working fine before the update. Here's an example of one of my scripts that is doing this that clearly shouldn't be:

public class HUDController : MonoBehaviour
{
public static HUDController Instance { get; private set; }
public GameObject healthIconPrefab;
public static Timer timer;
public Button gunButton;
public Button meleeButton;

public Text timerText;
public Text scoreText;
public Text coinText;

public RectTransform ammoCounter;
public HorizontalLayoutGroup healthLayoutGroup;
public Slider staminaSlider;

[HideInInspector] public Animator animator;
private static GameObject[] bulletIcons;
private static GameObject[] healthIcons;

private void Awake()
{

if (Instance == null)
Instance = this;
else
Destroy(gameObject);

DontDestroyOnLoad(this);

animator = GetComponent<Animator>();
timer = ScriptableObject.CreateInstance<Timer>();
}
}