If you suspect you have malware or a stuck browser homepage:
Lots of pop-ups, stuck on a website or suspect you may have malware?
Here is what to do for a basic fix (assuming you are using Safari on a Mac): with Safari running (open it if it is not), click Apple menu > Force Quit. Force Quit Safari.
Next, go to Apple menu > System Preferences and look for a Profiles preference area. If one is present, click on it and remove any preferences you do not recognize using the '-' sign.
Next, let’s get an app to remove malware the bad guys left behind. Download, install and run this excellent free app from here: malwarebytes.com/mac. Once the app is installed click on it in the menu bar (near the clock), click and Start Scan. It will prompt you to upgrade to their paid service whereby this app runs all of the time. I recommend against this. Running it manually works fine.
Use this app when you feel you have stumbled into a dark part of the Internet or you feel something funny is running on your Mac by, again, clicking the icon and clicking Start Scan.
Finally, hold the Shift key while and for a few seconds after opening Safari.
Restart your Mac.