My Fx preferences have stopped working!

[Odin2]

My default search engine (in about:preferences) is Google. Yet suddenly Yahoo search has hijacked my default searches! (And I don't even have Yahoo search as a listed search engine.) Also in about:preferences, I have "Use the address bar for search and navigation" unchecked--but the URLbar treats my entries as searches! What can I do to fix this?

[DanRaisch]

Have you recently installed or updated any extensions?
Have you tried starting Firefox in Mozilla Safe Mode? http://kb.mozillazine.org/Safe_mode
If no improvement using Safe Mode, do you have the same problem if you create a new profile and test it with no extensions or non-default themes installed?
http://kb.mozillazine.org/Profile_Manager
and
http://kb.mozillazine.org/Creating_a_ne ... on_Windows

Scan your system for malware -- Install and run these programs, consecutively, not simultaneously.
http://www.superantispyware.com/
http://www.safer-networking.org/en/index.html
http://www.bleepingcomputer.com/download/adwcleaner/
https://www.malwarebytes.org/

If these don't find it or can't clear it, post in one of these forums for specialized malware removal help:
http://www.spywarewarrior.com/index.php
http://bleepingcomputer.com/
http://www.spywareinfoforum.com/
http://aumha.net/viewforum.php?f=30
https://forums.malwarebytes.org/index.p ... topic=9573

[therube]

See, Defaulting to Yahoo even though I'm setting Google.

[Odin2]

Yahoo search hijack is gone! (Permanently, I hope.) All I did was to put Fx into safe mode and then restart in normal mode. I did not change a thing. Very strange indeed.