I am a student in school, and I usually use Unity to directly open some projects I created before. After a winter vacation, when I opened a Unity project as usual, I somehow reported Assertion failed: Assertion failed on expression: ‘! GetMainEditorWindow() ‘. After careful consideration, I found that my Unity account had expired and I needed to log in again. After logging in again, I finished filling in the relevant options, and the error would disappear. (Supplement: When this error existed, the original Unity project was not impossible to run, but after I ran the project, the Game interface would be stuck and unable to move the interface. This problem has been bothering me for a long time before, and then inexplicably disappeared. Now I find that I just logged in the Unity account… )