Can you try to uninstall and install again?

The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.

Try to decrease the value of the pref network.http.max-connections from 255 to a setting like 30 as used in Firefox 3 versions.

• https://support.mozilla.com/kb/Firefox+never+finishes+loading+certain+websites

Neither uninstalling/reinstall or resetting max-connections made no difference. Just tried FF version 6 and that didn't help. Any other suggestions?

Thanks.

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Which security software (firewall, anti-virus) do you have?

A possible cause is security software (firewall) that blocks or restricts Firefox or the plugin-container process without informing you.

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 to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.com/kb/Server+not+found
• https://support.mozilla.com/kb/Firewalls

Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

• https://support.mozilla.com/kb/Basic+Troubleshooting#w_8-make-a-new-profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If that new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

cor-el, I've added FF to exceptions and will test the outcome before going to Profile. I use VIPRE antivirus with its firewall disabled and Windows firewall for protection. I think the clue is that FF runs perfectly stable for the first half to one hour of browsing then deteriorates progressively.

The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.

Try to decrease the value of the pref network.http.max-connections from 255 to a setting like 30 as used in Firefox 3 versions.

• https://support.mozilla.com/kb/Firefox+never+finishes+loading+certain+websites

Have already tried reducing max-connections setting. This is now shaping into a wider problem. Have noticed some flicker on windows IE at certain financial pages although not nearly as severe as with FF. All flickering stops when 'work offline' is ticked. Disabling Vipre and firewall makes no difference.

You may need a clean install.

First export your bookmarks to a html file. (Bookmarks/Unsorted bookmarks will bring you History page where you can export your bookmarks). Note down your add-ons too.

Uninstall the old FF using free software like Revo Uninstaller. This will delete all the root directories and registries of old FF.

Now download the latest version of FF and install it. You can re-import your bookmarks from your saved html file.

You may still have to do what corel suggested above after the clean install of FF.

Thanks amkeew, this was also tried. I use Revo for all uninstallations, it's very efficient. Cleaned the registry with Uniblue before downloading FF from scratch. But why does FF remain rock stable for its first hour of use? What would cause an app to deteriorate over time?