As per as speed is concern there are lots of factors like downloading speed, server response time. I was also facing the same problem after update but in my case it was due to poor server response. You can check may be it is just because that.

Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• On Windows you can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• On Mac you can open Firefox 4.0+ in Safe Mode by holding the option key while starting Firefox.
• On Linux you can open Firefox 4.0+ in Safe Mode by quitting Firefox and then going to your Terminal and running: firefox -safe-mode (you may need to specify the Firefox installation path e.g. /usr/lib/firefox)
• Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Thanks for the reply, maha, but no server involved as far as I know, am using a stand-alone home computer. Download speed, while not great, is OK and unchanged from prior to update to v. 26.

The-Edmeister, this made a world of difference. Many thanks! Should have thought to try this myself. However, since I update every time Firefox prompts and did not have this problem in last version, it seems apparent that this is due to change in Firefox that makes it incompatible with add-ons, which I keep updated with Firefox utility. Therefore, do not consider problem solved, but do appreciate the help. Hope Mozilla can remedy this very soon.

The addon developer will have to update their addon to prevent such problem.

Wocka_Flocka_Flame, I suppose you are right. I will try (have, I suppose) to be patient. Thanks

Typical answers from mozilla that the problems lie with extensions. I have one extension installed and it is disabled and FF 26 runs at a snails pace. A browser that excelled early on has now been boggled down and is no better than any of the others.

It is possible that your security software (firewall, anti-virus) blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container 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.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

• https://support.mozilla.org/kb/fix-problems-connecting-websites-after-updating

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

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem.

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

pete1229, I absolutely agree. Firefox says these updates are important for security reasons, but it seems they ought to be able to maintain the (former) superior functionality of the browser.

cor-el, thanks for the effort, but I will for now, continue to live with selectively activating add-ons and wishing that Firefox can avoid making it tougher to use with their next upgrade.

cor-el, thanks for the effort, but I will for now, continue to live with selectively activating add-ons and wishing that Firefox can avoid making it tougher to use with their next upgrade.