Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

Thank you so much for your fast response.

It worked -- I closed Firefox and tried to reopen I got same response "Mozilla Firefox is not responding".

Am I going to have to open every time in Safe Mode? I do not want to do this as my Trusteer Rapport is then disabled.

HI, no this let's us/you know that it is probably one of the extensions you are running that is the issue.

Since no info came on anything including your extensions follow this :

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

In Firefox Safe mode these changes are effective:

• all extensions are disabled (about:addons)
• default theme is used (no persona)
• userChrome.css and userContent.css are ignored (chrome folder)
• default toolbar layout is used (file: localstore-safe.rdf)
• Javascript JIT compilers are disabled (prefs: javascript.options.*jit)
• hardware acceleration is disabled (Options > Advanced > General)
• plugins are not affected
• preferences are not affected

I would think it is your Trusteer Rapport but do not know what else you are running.

Please let us know if this solved your issue or if need further assistance.

I definitely do not want to operate Firefox every time with "safe mode"! It appears every time there is a Firefox update it affects my Trusteer Rapport which in turn creates problems opening Firefox. I see on other forum pages that others also have this problem.

I downloaded "Troubleshooting extensions, themes...." and the article "Troubleshooting Info page to help fix Firefox Issues". Hopefully by working my way through these articles I will resolve the problem.

Thanks for your help.

It could be Hardware Acceleration. How to disable Hardware Acceleration {web link}

It is possible that your firewall or other security software blocks or restricts Firefox without informing you, possibly after detecting changes (update) to the Firefox application. Remove all rules for Firefox from the permissions list in the firewall and let your firewall ask again for permission to get full, unrestricted, access for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/en-US/kb/server-not-found-connection-problem
• https://support.mozilla.org/en-US/kb/Firewalls
• https://support.mozilla.org/en-US/kb/fix-problems-connecting-websites-after-updating