Remove the Yahoo Toolbar

1. "Ctrl+Shift+A" (Add-ons Manager)
2. Select Puzzle piece on left-side for Extensions List
3. Find "Yahoo Toolbar" and click on "Uninstall" button, and restart Firefox. (if you really need to keep the Yahoo toolbar, you can hide the toolbar instead with customize, and still change all the search defaults as below)

Then to fix the default search engine used at the Location Bar, change the value of keyword.URL in about:config to one of the values shown in Location Bar search at MozillaZine.

• Google Search (Google search results page)
  http://www.google.com/search?ie=UTF-8&oe=UTF-8&q=

1. type in about:config into the location bar (in a new tab)
2. if the warning message nonsense comes up uncheck the box before dismissing the dialog message
3. filter on keyword
4. right-click on keyword.URL and choose "modify" then paste in the Google search engine string of your choice.
5. filter on defaulturl
6. right-click on browser.search.defaulturl (if it exists)and again choose "modify" then paste in the Google search engine string of your choice.
7. filter on ytff
8. right-click on yahoo.ytff.search.popup_src (if it exists) and again choose "modify" then paste in the Google search engine string of your choice, if adventurous might see if "reset" would remove and see if gone in next session (well not for those keeping the extension).
   -- above used in https://support.mozilla.com/questions/850287
9. If new tabs open with a Yahoo search, then in "C:\program files\Mozilla Firefox: Find the yahoo.xml file and delete it (/questions/892957)
10. If you find an extension call "New Tab" uninstall it (it is unwanted malware), this little gem came with a reinstall of "PicPick" software for me, do a custom install of PicPic without the yahoo anything.

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.org/kb/Safe+Mode

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

This problem seems to happen when Firefox updates; it seems to be a virus introduced by Mozilla - there is no 'option' to change it, and I guess they make millions out of forcing users to use Yahoo! in the location bar search.

I don't mind them doing stupid things like that - if only they would allow us the option to change it without having to rewrite code. Sorry, but we aren't all geeks!

I've asked for updates to be emailed, but I won't use FF until they allow me to unchoose Yahoo! easily and safely.

Just uninstalled firefox. It was painful, as it has been my primary browser for years. However, because the company refuses to let you download older versions and they refuse to fix the yahoo tab hijack issue, I'm off. I know 1 person's opinion doesn't matter, but I do a lot of web work and had reached a detente with my add-ons, so the tabs didn't pop-up. With the "forced/tricked" Firefox 13 update I lost all control. Pat yourselves on the back, you're becomin IE!

And evidence that FFhas jumped the shark - after 5 months, not one FF Fanboi has either explained the scam, or promised to fix it.

Yahoo! has been dying for years - seems a little spiteful to take FF down with it  :)

I got around this problem by: 1) altering the following statements in my prefs.js file located in my %/Mozilla/Firefox/Profiles/ directory to: user_pref("browser.search.defaultenginename", "Google"); user_pref("browser.search.defaultthis.engineName", "Google"); user_pref("browser.search.defaulturl", "http://www.google.com/search?ie=UTF-8&oe=UTF-8&q="); 2) then saving it, and 3) then changing the Properties of the pref.js file in Windows Explorer to Read-only. The last step ensures that the changes are not overwritten by Yahoo when Firefox is started. This solution works for me running FF13.0.1 on WinXP.