When I Added the prefeb of LeapHandcontrller in untiy I got the trouble. It shows as the following picture.
Changing to developer category. Have you tried the troubleshooting steps in these threads?
https://answers.unity.com/questions/668927/the-associated-script-cannot-be-loaded-on-every-sc.htmlhttps://forum.unity.com/threads/general-problem-with-scripts-the-associated-script-cannot-be-loaded.185994/
