Types and namespace not found...

Ok, so I’m new to Unity and C# but I wrote a tiny script which runs without a problem inside Unity. But when I try to export it (build) I get a bunch of errors all telling me types are not found, and it’s pretty much all the types I used… So it doesn’t find MonoBehaviour, Vector3 or Transform, Rigidbody2D, etc etc…

I can export the same project in HTML though, just not for windows.

I’m guessing I didn’t think of a simple thing that ruin everything but I didn’t find an answer fitting my problem. Sorry if I’m not clear, not english… Thanks in advance for your answers !

what path the problematic script is located in the project?

@Tritonmosquito What platform are you targeting (Android, iOS, Windows standalone, etc) ? And can you clarify by what you mean by “export”? Generally you choose Build (or Build and Run) from the File menu.