Hello
My answere might be late but if you encounter this problem go below link in your hard and remove files inside these folder (Roaming),(local).
"In the case if you could not find below path; Menu(View) -> Check the hidden items"
C:\Users\Mahsa{It can be your user name}\AppData\Roaming\MathWorks\MATLAB\R2020a
C:\Users\Mahsa{It can be your user name}\AppData\Local\MathWorks\MATLAB\R2020a
The problem can be cashe from unproperly closing or exiting from application.
Good Luck.
