Use an antivirus like Intego to remove malware from your system. Removing malware manually can have disastrous consequences for your system files, and you probably won’t be able to remove all the malware anyway.
If an app associated with macOS:Spigot-AY is on your Mac, then you likely have other adware threats installed too. To get rid of Spigot the safe way, you should follow our steps to run a full system scan using a secure antivirus program.