Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration 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 the suggetsion. I've now tried this, following the instructions you gave exactly as you posted, and it has made no difference.

Any other suggestions out there? I don't bookmark every site I use, and sometimes there'll be a URL in a magazine oir similar that I want to use and it's inconvenient (to say the least) if I have to type it as a search and thenm navigate to the site in question. This is becoming a 'dealbreaker' so far as Firefox is concerned; I'm now testing Chrome and Safari, but neither has the exact fuinctionality that I've become used to...

A possible cause is a problem with the file places.sqlite that stores the bookmarks and the history.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.com/kb/Bookmarks+not+saved#w_places-database-file

Thanks again - but still no joy. This is incredibly frustrating. And not least because although I've tested Chrome, Safari and (I know!) IE, none come close to offering the functionality and the ability to customise that FF has.

Does anyone have any other suggestions? It's clear from the various forums I've scanned that this is a problem that has been seen at least since v3...

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

Solved! Albeit not by your method of creating a new profile.

It turns out that ZoneAlarm was the culprit; the last auto-update made a small alteration in the ZoneAlarm Security Toolbar which I had not noticed; changing this back has re-enabled the Firefox Address Bar functionality.

Thanks again for persisting with me; your thoughts encouraged me to re-examine everything and so I found the culprit...

You're welcome