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My version has this on the launch page: URGENT! Your version of Firefox is no longer protected against online attacks. Get the upgrade - it’s fast and free! But when I go through the upgrade process it won't launch.


I persist in receiving the message that other copies of Firefox are running and so the new one cannot be installed. This happens even when I make sure that no copies on this shared computer are running. Computer is an iMac.

Additional System Details

This happened

Every time Firefox opened

This started when...

a couple of months ago

Installed Plug-ins

  • Gecko default plugin
  • Runs Java applets using the latest installed versions of Java. For more information: Java Embedding Plugin. Run version test: Java Information.
  • Shockwave Flash 10.1 r102
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in web pages. For more information, visit the QuickTime Web site.
  • Java Plug-In 2 for NPAPI Browsers
  • Juniper Networks Safari Extensions
  • Office Live Update v1.0
  • iPhoto6
  • The Flip4Mac WMV Plugin allows you to view Windows Media content using QuickTime.
  • RealPlayer Plugin


  • User Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv: Gecko/20101026 Firefox/3.5.15

More Information

I've done everything I know how to do within the parameters of the problem.

  • Top 10 Contributor
  • Moderator
10783 solutions 97057 answers

The Firefox 3.5.x branch has reached end-of-life and is no longer maintained.
You will no longer receive security updates for that Firefox version.
You can update Firefox via "Help > Check for Updates" or download and install the latest Firefox 3.6.x or 5.0.x version if updating doesn't work.

If you have problems with updating or with the permissions then easiest is to download the full version and trash the currently installed version to do a clean install of the new version.

Download a new copy of the Firefox program and save the DMG file to the desktop

  • Trash the current Firefox application to do a clean (re-)install
  • Install the new version that you have downloaded

Your profile data is stored elsewhere in the Firefox Profile Folder, so you won't lose your bookmarks and other personal data.