You can download firefox from www.getfirefox.com.

Please note that you are running a VERY old version of Mac OS, and if possible you should update to a more modern version of Mac OS. https://support.apple.com/en-us/HT201475 These old versions of Mac are insecure and have many issues, not to mention the fact that Firefox will probably drop support for Mac 10.6 eventually.

Hello, try to delete Firefox icon from the dock and then create a new icon by dragging the Firefox application to dock.

than you

If there a problem with updating or with the permissions then best is to download the full version and trash the currently installed Firefox application to do a clean reinstall.

Download a new copy of the Firefox application and save the Disk Image file to the desktop

• Firefox 45.0.1: *https://www.mozilla.org/en-US/firefox/all/

• Trash the currently installed Firefox application (open the Applications folder in the Finder and drag the Firefox application to the Trash) to do a clean reinstall
• Install the new version that you have downloaded
• https://support.mozilla.org/kb/Installing+Firefox+on+Mac

Your personal data like bookmarks is stored in the Firefox profile folder, so you won't lose personal data when you uninstall and reinstall or update Firefox, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

Make sure that Firefox gets installed properly.

Open the Firefox Disk Image file and drag the Firefox application to the Applications folder on your hard drive. You shouldn't double-click the Firefox application to run it from the Disk Image, but instead drag it out of the DMG folder.

• http://kb.mozillazine.org//Installing_Firefox#Mac_OS_X
• https://support.mozilla.org/kb//Installing+Firefox+on+Mac