Hello jcvogel,

It sounds like you are dealing with search.yahoo.com redirect virus, which is malware that you of course need to get rid of.

Go to the Firefox menu (≡) => Add-ons => Extensions and look for any unfamiliar or suspicious looking extensions.

When you find any : remove them.

Do the same in Windows Control Panel => Programs

However : most malware will be 'hiding' somewhere , so let's run malware scans (even though you already have run some) :

Further information can be found in this article : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. They all work differently - what one program doesn't pick up, the other might.

Also see : https://www.pcrisk.com/removal-guides/8835-search-yahoo-com-redirect

Mit Malwarebytes (neueste Version) wird angezeigt, dass selbst der von Ihnen angegebene Link bei PCRisk Malware enthält! Sehr hilfreich erscheint mir Ihr Tipp nicht ...

jcvogel said

Mit Malwarebytes (neueste Version) wird angezeigt, dass selbst der von Ihnen angegebene Link bei PCRisk Malware enthält! Sehr hilfreich erscheint mir Ihr Tipp nicht ...

Would you please follow all the steps in my post  ?

But as my advice doesn't seem very helpful to you : let's hope that somebody else will come up with better advice ......

Vielleicht hatten wir beide gestern keinen so guten Tag. Falls ich mich in meiner Wortwahl vergriffen habe, bitte ich um Entschuldigung. Es war nicht böse gemeint, ich war eben völlig frustriert. Grüße - Jürgen Vogel

jcvogel said

Falls ich mich in meiner Wortwahl vergriffen habe, bitte ich um Entschuldigung. Es war nicht böse gemeint, ich war eben völlig frustriert. Grüße - Jürgen Vogel

Absolutely no need to apologize - we all have our 'moods' .....

But as my suggestions didn't help and you're apparantly not dealing with search.yahoo.com redirect virus , and you're settings in Options => Search are correct : When exactly is it that you see Yahoo appear  ?

Should it be at startup : then you could check the setting for your
home page - but I doubt if that's the case, otherwise you would have mentioned it.

I'm going to ask a somebody for help.

hello, you may have malicious addons present. please perform all these steps:

1. refresh firefox (this will keep your bookmarks and passwords)
2. afterwards go to the firefox menu ≡ > addons > extensions and in case there are still extensions listed there, disable them.
3. finally run a full scan of your system with different security tools like the free version of malwarebytes and adwcleaner to make sure that adware isn't present in other places of your system as well.

Troubleshoot Firefox issues caused by malware