Here's how to get rid of everything from Mac OS X: #Locate and delete your profile folder (bookmarks, history, passwords, etc) - [[Profiles - Where Firefox stores your bookmarks, passwords and other user data]] #Click the Finder icon in the dock. On the menu bar, click the Go menu, hold down the option or alt key and select Library. A window will open containing your Library folder. #*In the Library window, locate and delete the Mozilla folder #*In the Library window, locate and open the Preferences folder #**In the Preferences folder, search for "mozilla" and delete all the files that you find.