Unity: "The referenced script (Unknown) on this Behaviour is missing!"

Question

Sometimes when I start my game, I get pointless warnings. I do not know where they come from and I do not have any objects that address a script that does not exist. How can I remove or fix these messages?

Console:

Inspector:

When I right click on the icon of the file in the inspector I get two possible options. Both of them do not work or when I try to click on them nothing happens.

Inspector context menu:

Answer 1

It happens when the file and the name class has not the same name.

Example:

• The file is named SingleCube.cs
• The class definition is public class Cube : MonoBehaviour

In this case, Unity is not able to link the file and the class. Both have to have the same name.

• The file should be SingleCube.cs
• And the class definition public class SingleCube : MonoBehaviour

Answer 2

I had this same issue as well. I think it's caused by deleting the default scene but not changing the "Scenes in Build" in the build settings. Here's how I fixed it.

1. Go to your build settings (File > Build Settings). There should a greyed out box that says "deleted". This is the (now missing) default scene.
2. Right click on it and remove it
3. Add your current scene