How about trying a FTP Program Just because there is not a addon you want to revert. Try using a real FTP Program like Filezilla https://filezilla-project.org/client_screenshots.php Going back : unfortunately 56.0.2 is no longer safe to use for every day usedue to security issues, but 52.5.0 ESR is! It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ <b>Note : Legacy Extensions will be deleted or removed in any version update after May 2018.</b> You should make a backup of your Profile before going back and just because: https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles Please let us know if this solved your issue or if need further assistance.