hi, google should already be the default search provider in firefox. in case yahoo is taking over without you opting in to that it may be an issue with adware on the affected system. #please go to the firefox ''menu ≡ > addons > extensions'' & remove any suspicious entries (toolbars, things that you have not installed intentionally, don't know what purpose they serve, etc). #in case you're on windows, also go to the windows control panel / programs and remove all toolbars or potentially unwanted software from there. #finally, run a full scan of your system with different security tools like the [https://www.malwarebytes.org/antimalware/ free version of malwarebytes] & [https://toolslib.net/downloads/viewdownload/1-adwcleaner/ adwcleaner], which are specialised in adware and browser hijackers. [[Remove a toolbar that has taken over your Firefox search or home page]] [[Troubleshoot Firefox issues caused by malware]]