Hello julia_cohen If there is an issue with update or permissions '''''the better, quickest and safest 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 Installing Firefox on Mac] thank you Please mark "Solved" the answer that really solve the problem, to help others with a similar problem.

Note that you may already have the latest Firefox 16.0.2 version installed. You can check that via the Firefox menu and select About Firefox *https://support.mozilla.org/kb/Finding+your+Firefox+version