Wow that is a big jump from ver 36 to 56. I would say this is the reason.

I do not know the compatibility of profiles between such a gap. I would suggest exporting your bookmarks as HTML and screen shoot your passwords just in case. https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Suggest uninstall it all as nothing is the same in code wise.

Note : Firefox 56.0.2 is current release https://www.mozilla.org/firefox/all/ Full Version Installer Note : Firefox 57 Quantum release date Nov 14th https://www.mozilla.org/en-US/firefox/quantum/ Note : Legacy Extensions will be disabled and or removed.

Note : Flash Player Version: 27.0.0.183 is current version

Please let us know if this solved your issue or if need further assistance.

I'm a Windows person. My understanding of uninstalling an old version of Firefox on Mac is limited, but I've read that it involves "trashing" a file -- without removing any of your accumulated data. Do either of these articles help? If they do not automatically adapt to MacOS, please expand the Editing Tools section in the left column and use the OS selector to choose MacOS.

• Download page for a new "full" installer: https://www.mozilla.org/firefox/all/
• Usual procedure: Update Firefox to the latest release
• If you need to remove the old version: Uninstall Firefox from your computer
• To then install the latest version: How to download and install Firefox on Mac