Users are reporting that this is caused by add-on toolbars, particularly ones that have "community toolbar" in the name. Could you check for any of those and disable them and see whether that helps?

You can review and disable extensions on the Add-ons page. Either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then, if in doubt, disable.

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.

Does that help?

I should mention that an out-of-date extension also can create issues. Above the list of extensions is a "gear" button where you can choose "Check for Updates".

Same problem, have no add-ons or extensions enabled...

Hi MattJB, is this the only dysfunction with the interface on your Windows 8.1 system? I'm asking because in another thread it was discovered that Firefox does not work correctly with downloadable Windows themes, for example, the "3-bar" menu button doesn't work, either. See: https://support.mozilla.org/questions/1012745?page=4#answer-630045 and following

To be honest it's been a bit of a nightmare - have had the laptop maybe 6 months and have reset or redownloaded Firefox about four times things got so messy. Went for a while not being able to use Google (Firefox thought it didn't have a valid security certificate), the home page and others got invaded by Yahoo, then by Megabrowse, various other addons seemed to slow the whole thing down to the point of giving up...

And I haven't changed any settings, downloaded apps or addons, etc, very basic usage of both the laptop and the internet.

The new tab issue can be solved by re-setting Firefox from the safe start mode by the way...

Hi MattJB, you may also want to check for additional unwanted software.

I suggest starting here:

Open the Windows Control Panel, Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed items that snuck in with some software you agreed to install. Take out as much trash as possible here.

Next, you can "mop up" many remaining issues with the scanning/cleaning tools suggested in this support article: Troubleshoot Firefox issues caused by malware. Those are free and take a long time to run. If they seem to finish quickly and especially if they require a purchase to clean your system, you may have a serious infection. Try the specialized forums listed in the article.

Some problems occurs when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}