I have used Firefox on my Mac (Catalina 10.15.6) for 3 years. Yesterday I got a message: 'The application “Firefox.app” can’t be opened.' Since then I have repeatedly deleted Firefox and all it's associated files; downloaded ver 79 and the results have been the same. So I went to Beta ver 80 and got the same results. As a user of Firefox since it was introduced as Mozilla, I find everything else unsatisfactory and hope someone can help