Can't add script component because the script class cannot be found?

Question

Yesterday I updated unity from unity5 to 2018.2.2f1. Unity scripts are not loading after Update 2018.2.2f1.

Once I try to play the Scene the scripts are not loaded a

Answer 1

Checking the console bugs and fix them is a good way to solve the problems "Can't add script component because the script class cannot be found?", although the bug seems to be irrelevant. This works for me when I fix a bug in the other script.