For those that really need an earlier version of Firefox * ftp://ftp.mozilla.org/pub/firefox/releases/ When reinstalling Firefox from a download, Firefox must be down once the installation starts. When the installation finishes, don't let the install start firefox for you. Instead end the install and start Firefox in your normal manner, thus preventing creating a new profile which does not have your bookmarks cookies, etc (but your old profile would still be around and would). ---- Research your extensions, some may have updates, some may be found in the developer comments on the add-on, or on the "View all versions" link which is part of the Release notes at the bottom of the add-on page. [https://addons.mozilla.org/firefox/addon/is-it-compatible/ Is It Compatible? :: Add-ons for Firefox], Are your add-ons compatible with the next version of Firefox? Find out straight from the Add-ons window!