Hi, I would say that the previous answer was probably mine. But this shows this is the 1st time you have asked this question under this name. As for loosing settings during a reinstall, your profile is saved so there would be no loss and I ask that you back it up also. A refresh would be worse.

As i understand it those 2 are fixes for the issue.

Is possible in the updates that a file is clipped or packet loss. None of that with a install with a Full Version Installer. Or a file is corrupted and is why delete the folders.

Sorry no answer for you.

Hi everyever, I can't believe you've put up with this for 2-3 months! And to get you a more "surgical" solution than burning down your Firefox settings, let's get a little more detail.

Your default search engine setting is getting changed. Can you describe the pattern for when that occurs?

• Every time you exit Firefox and start it up again
• Only when you shut down and restart Windows
• On a schedule, or randomly, not tied to either of the above

Do any other settings change, such as your home page?

And finally, when you see the changed default, is its name just "Yahoo" or is it a slightly different name such as "Yaahoo" or "Yahoo Search Engine"?

The problem remains whether you exit or restart Firefox, and whether you shut down or restart or hibernate Windows.

Perhaps it wasn't clear -- the name Google remains unchanged and marked at the top as the default search engine, and the search bar also shows Google listed first -- yet when the search is engaged, Yahoo comes up regardless.

And wherever and whenever the name Yahoo appears, whether on the options page or on the search webpage ,it is spelled correctly and with the Yahoo logo apparently as it should be -- but perhaps that word should be put in quotes ("apparently"), as it is not inconceivable that a logo could be imperceptibly tampered with.

Okay, that all points toward either (A) an extension or (B) a bad connection setting.

Extension

You can view, disable, and often remove unwanted or unknown extensions on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• Command+Shift+a (Windows: Ctrl+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• type or paste about:addons in the address bar and press Enter/Return

In the left column of the Add-ons page, click Extensions.

Then cast a critical eye over the list on the right side. Any extensions Firefox installs for built-in features are hidden from this page, so everything listed here is your choice (and your responsibility) to manage. Anything suspicious or that you just do not remember installing or why? Any that have the word "search" in the name?? If in doubt, disable (or remove).

Any improvement?

Connection

You can check that here:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type proxy and Firefox should filter to the "Settings" button, which you can click.

The default of "Use system proxy settings" piggybacks on your Windows/IE "LAN" setting. "Auto-detect" can lead to a flaky connection. You may want to try "No proxy".

Any difference?

Many thanks! You were right -- 2 insidious "mapping directional" Add-ons , which shouldn't be there, were listed on the Extensions page. As soon as these were removed, the correct default search engine came to the fore and properly functioned as previously. Thanks again - Everyever

Hi,Glad to hear that your problem has been resolved. If you haven't already, *Please select the Solution that solves the problem*. This will help other users with similar problems find the solution more easily. Thank you for contacting Mozilla Support.

The "Helpful Reply" didn't work for me.. I believe Firefox was hacked. I have no extensions, and the "No Proxy" didn't help either... sniff!

This happened after the Firefox update ( updates never end well :-)

Hi lamboom, are you still using a Mac?

Could you start a new question with your Firefox configuration details?

https://support.mozilla.org/questions/new/desktop/fix-problems

As always, scroll down past suggestions to continue with the form.

Also, please note which symptoms you're seeing:

• On the Preferences/Options page, the default search engine setting gets changed to Yahoo (what's the name of the one that appears) -- and if I change it
  • It changes back the next time I quit and start Firefox again
  • It changes immediately or refuses to change
  • It changes back randomly

• Yahoo has taken over the home page

• Yahoo replaces the new tab page