Does the browser.newtab.url preference change, or is it being ignored?

If it changes after you exit and restart Firefox, check for a user.js file as described in this article: How to fix preferences that won't save.

If it's ignored, check for an unwanted extension in the Add-ons page:

Ctrl+Shift+a or orange Firefox button (or Tools menu) > Add-ons

On the left side, click Extensions, then disable ALL nonessential or unrecognized extensions.

Usually a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

By the way, a reset on browser.newtab.url should display the 9-thumbnail page. To get a blank page...

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste newtab and pause while the list is filtered

(3) Double-click the browser.newtab.url preference, change the URL to about:blank and click OK.

It should take effect immediately (unless an extension is overriding it) and you can test by pressing Ctrl+t.

No, as I said in the first post, I already did this step and the same nonsense AVG search address shows up. I never get a blank tab--not if I restart or right after doing the about:config steps.

Thanks! This actually solved the problem. But now that I disabled the AVG safe search, does that mean that my AVG antivirus is not working when I am online?

Which prefs show if you do a search for isearch on the about:config page?

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe Mode start window.

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

• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml

Hopefully you'll find the responsible extension, or if there are many to review, you could try Firefox's Safe Mode as a quick knock-out test, since it disables all extensions. More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference? That's obsolete, I should have reloaded first.

CT3289663_Firefox.csv smartbar.conduithomepageslist smartbar.conduitsearchenginelist smartbar.conduitsearchurllist smartbar.searchfromaddressbarsavedurl smartbar.keywordurlselectedctid

"AVG Safe Search" is supposed to just indicate whether links in your search results are safe, I don't know why it's changing your new tab page. I'm not sure whether there are settings in AVG to fine-tune its behavior, or whether you're stuck with that combination of features.

Anyway, AVG at your system level will just keep working.

Sorry, I'm only average at technology. How can I tell if an extension is causing the problem? I am now in safe mode and when clicking on tools>add ons>appearance I get "default 24.0 disabled."

But regardless, the problem is solved, right? And AVG is still protecting my computer when I do searches?

"Which prefs show if you do a search for isearch on the about:config page?

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Firefox/Tools > Add-ons > Appearance).

   Do NOT click the Reset button on the Safe Mode start window. 

   https://support.mozilla.org/kb/Safe+Mode
   https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes "

Safe Mode can tell you that one of your extensions is the problem, but not which one. Solving that puzzle requires manually disabling/re-enabling. I think you've already solved it by disabling the AVG Safe Search extension.

Prefs that start with CT are most likely from a Conduit Toolbar (you listed other Conduit related prefs), so you may have or previously had such a toolbar installed and stil have those prefs.

You can also check for the presence of a user.js file in the Firefox profile folder if you haven't done this yet.

• http://kb.mozillazine.org/Preferences_not_saved

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)

Note that Windows hides some file extensions by default.
Among them are .html and .ini and .js and .txt, so you may only see a name without file extension. You can see the real file extension (type) if you open the Properties of the file via the right-click context menu.

Thanks a lot for the help guys! :)

Yes, I had some conduit toolbars installed when I downloaded something. Unfortunately they automatically became my default search engines and toolbars but I disabled them in tools>addons>extensions. Thanks again!

I would just like to add to this thread. I have tried everything and every way listed here and found my own solution, for those of you who were having the same issue as me.

1. Type "about:config" in your search bar

2. Click "I'll be careful, i promise"

3. Type "newtab" in the search bar

4. Find "avg.userPreferences.newtabDisabledByUser"

5. Set value to true by either doube clicking or right click > toggle

This immediately deactivated the AVG new tab feature and reset my browser to it's default settings.

Hope this helps!