Cannot reset browser.newtab.url string.
Remove user.js file and removed pref.js file. I am still unable to change the BROWSER.NEWTAB.URL value it currently reads (http://search.conduit.com/?ctid=CT3310393&octid=EB_ORIGINAL_CTID&SearchSource=69&CUI=&SSPV=EB_SSPV&Lay=1&UM=2&UP=SP4C847359-3AA0-4431-97B5-C13E78282F38).
hello, it may be an issue with adware present in your firefox profile.
please go to firefox > addons > extensions & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc).
also go to the windows control panel / programs and remove all toolbars or potentially unwanted software from there and run a full scan of your system with securitytools like the free version of malwarebytes & adwcleaner.
Check for the presence of a mozilla.cfg file in the Firefox program folder to initialize some prefs.
This also involves the presence of a .js (JScript) file, probably in "defaults\pref" folder, that specifies to process this mozilla.cfg file.
If you have .js files apart from the channel-prefs.js file, that sets app.update.channel, in the defaults\pref folder then open this file in an editor like Notepad and please post its content.
Also please post the content of the mozilla.cfg file.
There shouldn't be a mozilla.fcg file present unless you've created it yourself to initialize some prefs.
If you have this mozilla.cfg file then best is to do a clean reinstall and delete the Firefox program folder before reinstalling a fresh copy of Firefox.
If you go into Control Panel > Add or Remove Programs, you will find the offending program that is preventing the reset. It is called "Search Protect". Simply uninstall the program and chose the checkbox that says something about "Return to my original settings". Once it is uninstalled, you shouldn't even have to go into about:config to change the settings, I believe it actually does so automatically.
ho windows 7 e dopo vari tentativi sono riuscito a superare il problema andando in C:\Users\......\AppData\Roaming\Mozilla\Firefox\Profiles\ao2hnapv.default e modificando con un editor pref.js impostando una diversa url nella chiave browser.newtab.url. salvato il file e fatto ripartire FB.... sembra che funzioni tutto