You should be able to downgrade to Firefox 3.6 without problems, although that may not remain supported for much longer.

Will Firefox 3.6 open in safe mode do not make changes from the list in the first window, just click on continue. The problem may be caused by the updated plugins, in which case maybe you should consider uninstalling them, and the possibility of reinstalling the plugin versions that worked, once you have Firefox running again.

You may be interested in the thread /questions/877611

Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.com/kb/Safe+Mode

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

Thanks for your reply. It 's beginning to seem, however, that this version of F.F. will not be supported much longer and it would hardly be worth the trouble to reinstall it. So, I guess I'll have to bite the bullet and upgrade to Snow Leopard, even if that means purchasing some more RAM. At least then I'll be able to use the Google Chrome browser and keep my present computer up and running for a couple more years.

There was a post that Fx3.6 would be continued till further notice, but at least in part that may depend on what happens with propose enterprise releases. Fx3.6 continues to support your OS and to be secure.

I suspect versions for your OS will remain available and installable

Thanks John99,

I'll try again to find a site to download Fx 3.6.0. So far the closest thing I've been able to find to it was Fx 3.6.13 and replacing Fx 3.6.22 with that left me still unable to open the browser, in safe mode or otherwise.

3.6.0 all languages for mac:

ftp://ftp.mozilla.org/pub/mozilla.org/firefox/releases/3.6/mac/

Whilst you could use Firefox 3.6.0 that is not secure and a security risk therefore can not be recommended. It is likely the earlier version only really differs because of security patches. (see https://www.mozilla.org/en-US/firefox/3.6/releasenotes/ to https://www.mozilla.org/en-US/firefox/3.6.22/releasenotes/ )

If you do have security software it is likely to allow a specific version of firefox, and may block other versions as being unrecognised.

I do not see why Firefox 3.6.22 can not be used. It should open on your system. Have you got security software that may be blocking changes or new installations. Or maybe if you have been using an insecure version, and do not have security software then it is conceivable the problem is because of malware.

Try a clean reinstall of firefox 3.6.22, involving deleting the program files but not the profile files, and consider also trying a new clean profile (create an additional profile, do not delete the existing one - you would loose valuable information).

• see http://kb.mozillazine.org/Standard_diagnostic_%28Firefox%29#Clean_reinstall
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox
• basic troubleshooting
• is my firefox problem a result of malware
• firefox will not start

Definitely the older versions aren't supported any longer and are missing hundreds of security patches that are in the latest versions of Firefox.

Definitely the older versions aren't supported any longer and are missing hundreds of security patches that are in the latest versions of Firefox.

Thanks for the info, Idea2

Thanks for all the info John99 but, not being a techie I'm afraid I might get myself in trouble trying some of the things you suggest. Think I'll just install some more RAM and upgrade my OS to Snow Leopard.