I don't think there is a current version of Firefox that will work for Snow Leopard. The minimum OS X version supported as of Firefox 49 is 10.9 Mavericks. Snow Leopard was supported in the previous 45 ESR build but since the newest 52 ESR version came out, that is now obsolete. *https://www.mozilla.org/en-US/firefox/52.0/system-requirements/ *https://support.mozilla.org/en-US/kb/firefox-osx Is it not possible for you to upgrade to Mavericks?

You can use this link: https://download.mozilla.org/?product=firefox-45.9.0esr&os=osx&lang=en-US http://download.cdn.mozilla.net/pub/firefox/releases/45.9.0esr/mac/en-US/ https://www.mozilla.org/en-US/firefox/45.9.0/system-requirements/