So at this point, you are back on Firefox 83? To change to your earlier profile, try this: '''Profile Manager Page''' Inside Firefox, type or paste '''about:profiles''' in the address bar and press Enter/Return to load it. This page should list at least one profile and could list many. (Each profile has two folders and one or more buttons. Do not use any Remove buttons!) The profile that Firefox is currently using will have this: '''This is the profile in use and it cannot be deleted.''' Do you have another profile named default or default-release or default-''longnumber'' listed on this page? If so, you can check whether it is the one you were using before by clicking its '''Launch profile in new browser''' button. If it isn't what you want, simply close that new window. If it IS what you want, back on the about:profiles page, click the '''Set as default profile''' button for that profile so Firefox uses it automatically at the next startup. Success? And what was it you didn't like about Firefox 83?