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How do I make sure that all Firefox sessions are closed so I can download 6.0? Keep getting a dialogue box saying that only 1 can be open at a time. Only 1 IS open, and I need this update to meet a system requirement for an online class.


Not sure what I can add to that. I actually shut down my Mac to make sure no sessions were open before I tried again. Help.

Additional System Details

This happened

Just once or twice

This started when...

I tried to download 6.0

Installed Plug-ins

  • The QuickTime Plugin allows you to view a wide variety of multimedia content in web pages. For more information, visit the QuickTime Web site.
  • Displays Java applet content, or a placeholder if Java is not installed.
  • Shockwave Flash 10.3 r183


  • User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:5.0.1) Gecko/20100101 Firefox/5.0.1

More Information

Did not happen once or twice - try 6 times. That's how many times I tried to download.

Hamid Moazzami 14 solutions 86 answers

Why don't you download Firefox 6.0 as a installation pack and then install it. You can do it here:

Download Firefox All systems/ Languages

Firefox installation will do the housekeeping for you!

Don't forget to hit 'Solved it' Button if you found this helpful so you close the topic.

Question owner

Same result: A copy of Firefox is already open. Only one copy of Firefox can be open at a time.

Hamid Moazzami 14 solutions 86 answers

Try closing the program with something like a task manager. If that didn't do the trick, try to uninstall the last version. Then install the pack. If you can't download FF new versions, try to use other browsers like Safari as you're using MAC OS and download the pack and install a clean version.

SafeBrowser 550 solutions 2392 answers

Must be the "hang at exit" problem.

  1. Stop the Firefox process:
  2. Why Firefox may hang:
  3. Use Firefox Safe Mode to find a problem with an Extension or Plugin:

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