Hello,

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.)

• You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
• 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.

Thank you.

It sounds similar to these extension-related issues:

• I get this message on the new Firefox v22 -Error: Illegal operation on WrappedNative prototype object - "The ones causing that problem where all related to google : 1 - Google Search by Image / 2 - Search By Image (by Google) / 3 - DeeperWeb - Boost and Customize Google Search"

• I just upgraded to FireFox 22.0, and now I get a Javascript error (Error: Illegal operation on WrappedNative prototype object). What can I do? - (A) "I found the faulty extension - CloudMagic"; (B) " For the moment I found a workaround (disabling the XINHA CSS plugin)."

Safe Mode will disable all extensions so you can get a quick check on whether one of those is likely to be the problem.

To review and disable all but the most essential extensions, you can use this page:

orange Firefox button (or Tools menu) > Add-ons > Extensions category

Any luck?

I unchecked the hardware accellerator. I disabled all of the extensions, and there were quite a few. Only the Adobe Reader I left on and chose to update. It seems to be working now. Thank you very much.

Every time I open a new tab, I get the error message, "The address isn't valid - The URL is not valid and cannot be loaded." I've tried all of the suggested fixes and it's still happening. Help would be appreciated. Thanks very much.

Hi geofre, is this when you create an empty tab -- using the "+" button or Ctrl+t or a menu entry for new tab?

There is an internal setting for what should be displayed in a new tab. Let's try updating that first. If it doesn't work, you may have an add-on that is overriding it.

(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 filter box, type or paste newtab and pause while the list is filtered

(3) Double-click the browser.newtab.url preference and enter the desired value from the following 4 options:

(i) Page thumbnails (default)

about:newtab

(ii) Blank tab

about:blank

(iii) Built-in Firefox home page

about:home

(iv) Any other page

full URL to the page

Press Ctrl+t or click the "+" button to open a new tab and verify that it worked. Fixed?

1. In the Location bar, type about:config and press Enter. The about:config "This might void your warranty!" warning page may appear.
2. Click I'll be careful, I promise!, to continue to the about:config page.
3. Type browser.newtab.url
4. Double click the first result, a new window should now show.
5. Type about:newtab in the box.
6. Hit ok and load a new tab. Does it work now geofre?

Clearly some of the addons were out of sync. When I went in and disabled everything, I no longer had the problem. I was surprised there were so many. Thank you for your help.

Hi jsher2000 - I was getting that error message regardless of how I opened a new tab. When I did as you suggested and chose about:newtab I still got the error message; when I switched to about:blank, no error message. Thanks for your help.

Hi Waka_Flaka-_Flame - As I explained to jsher2000 when I chose about:newtab I still got the error message; when I switched to about:blank, no error message. Thanks for your help.

Hi JudyLeeThurber - I'd already tried disabling all addons - didn't work. But thanks for your input.

geofre, you may need to reset firefox.

• Refer to the Refresh Firefox - reset add-ons and settings article for more.

Did the reset - went back to getting the original error message. Followed what jscher2000 suggested, using about:blank, and error message is gone. Thanks.

Hi geofre, I'm puzzled by the error message. I wonder whether some external privacy or cleanup software is removing the thumbnails that usually appear on the about:newtab page? If you don't miss the thumbnails, it's probably not worth your time to investigate further. If you notice any other mysterious behavior, it could be related, so please post back in that case.

Hi again, jscher2000 - I went back and re-installed Firefox. At first I freaked out because I thought I'd lost all of my bookmarks, but I found the answer to that little puzzle easily enough and now all is well. True, I still don't know what was wrong in the first place, but everything is working exactly as it should now. Thank you, and all who responded, for your help.