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Why won't Firefox open at all?

  • 3 replies
  • 1 has this problem
  • Last reply by FredMcD

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Firefox updated yesterday and ever since then it will not open at all. I am running the latest macOS on a MacBook Air. It just bounces on the Dock once then doesn't open at all. I have tried uninstalling and reinstalling AND I even tried to downgrade back to 70.0.1 and it STILL didn't work. It won't even open in Safe Mode.

All Replies (3)

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Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

  • Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
  • Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

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It only works if I run it off the downloaded disk drive. Also I am running it on a Mac and my firewall is turned off. I have no internet security software.

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Start your Computer in safe mode with network support. Then start Firefox. Try Secure websites. Is the problem still there? Starting Any Computer In Safe Mode; Free Online Encyclopedia