Hello doubleg, If there is an issue with update or permissions the better and easiest way is to download and install firefox: 1. Download a copy of the latest firefox from http://www.mozilla.org/en-US/firefox/all.html 2. '''Trash''' the current Firefox 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=fx18 Installing Firefox on Mac] thank you Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

I have the same problem. Is firefox not supporting Mac anymore ?

Hi oly123456, fully supported mac from 10.6 and above, [http://www.mozilla.org/en-US/firefox/18.0/system-requirements/ Firefox 18 System Requirements] thanks

I had to uninstall and reinstall it again. Thank you.

you are welcome