Hi blkjakf8 1. Download your copy from : ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/16.0.2/mac/ 2. '''Trash''' your current Firefox 19 application to do a clean install. 3. Install the version that you have downloaded. Do not select to remove your personal data, your profile data is stored elsewhere in the [http://kb.mozillazine.org/Profile_folder_-_Firefox Firefox Profile Folder], so you won't lose your bookmarks or other personal data. see also: [https://support.mozilla.org/en-US/kb/install-firefox-mac?redirectlocale=en-US&redirectslug=Installing+Firefox+on+Mac#os=mac&browser=fx19 Installing Firefox on Mac] you already known that [https://support.mozilla.org/en-US/kb/firefox-no-longer-works-mac-os-x-10-5#os=mac&browser=fx19 Firefox no longer works with Mac OS X 10.5], see in the link '''Option 3: Continue to use Mac OS X 10.5 and Firefox 16''' thank you

You can also consider to install the last Firefox 10.0.x ESR version as that version is more recent than the Firefox 16.0.2 version. * https://ftp.mozilla.org/pub/mozilla.org/firefox/releases/10.0.12esr/ * http://www.mozilla.org/en-US/firefox/10.0.12/system-requirements/