It's possible you have Malware on your computer. Please follow these steps to confirm: * [[Troubleshoot Firefox issues caused by malware]] (Please run all the anti-malware tools here) * Ensure you have all windows updates installed, and that Windows Defender is enabled (you don't need any other anti-virus) * [[Refresh Firefox - reset add-ons and settings]] This will remove any malicious settings. After following all those steps, try to set your home page again,