''I think you probably already know this part, but just in case:'' The last version of Firefox for Mac OS 10.11 is the Extended Support Release of Firefox 78, which is pretty close to retirement. You can still get it from the following page -- make sure to choose 78.15.0esr and not the newer one. https://www.mozilla.org/firefox/all/#product-desktop-esr <img src="https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-10-12-11-08-54-c019f7.png" References: * [[Firefox Mac OS X 10.9, 10.10 and 10.11 users move to Extended Support Release]] * [[How to download and install Firefox on Mac]] ---- ''<p>rdservants [[#question-1354150|said]]</p>'' <blockquote>There is a profile in the Application Support folder and old ones on the desktop. </blockquote> Firefox is looking for a specific named profile. That path is listed in the install.ini and profiles.ini files. I don't have a Mac to confirm, but I think those would be under ''~/Library/Application Support/Firefox'' '''What did you try here:''' ''<p>rdservants [[#question-1354150|said]]</p>'' <blockquote>I followed the directions to access the profile manager through Terminal, but it didn't work. </blockquote> The Profile Manager should show the list of profiles from those files, but since the current default profile isn't at the saved path, you can't launch Firefox using that profile. However, can create a new profile to get up and running with Firefox again. Then we can discuss migrating data. Refs. * [[Profile Manager - Create, remove or switch Firefox profiles]] * [[Recovering important data from an old profile]]