Over the past week on my iMac, when trying to download any files via Firefox, I get the following errors. '''Downloading could not be saved, because an unknown error occurred. Try saving to a different location.''' I've already gone through all of the steps on this support page: https://support.mozilla.org/en-US/kb/cant-download-or-save-files I attempted to go to about:config to update my browser.download settings but some of them were missing. When I went to Preferences, I was unable to change even change the Downloads folder (the Choose button did not work). I uninstalled and re-installed Firefox 90.0 (64 bit) I am out of ideas and I really need help. Can someone please assist me? Thank you. Dean