Antivirus Software
No matter what OS you are on, you will need antivirus software. AV-Test registers over 350,000 new pieces of malware and potentially unwanted applications (PUA) every day. Thus, it is necessary for you to take preventative measures to reduce the risk of malware.
Windows: Windows Security
Windows Security (known as Windows Defender Antivirus before Windows 10 May 2020 Update, Windows Defender before Windows 10 Creators Update, or Microsoft Defender Antivirus before Windows 11) is an anti-malware component of Microsoft Windows.
Windows Security is built-in into Windows 8 and above. For Windows older than Windows 8, Windows Defender only removes spyware, and a third-party Antivirus Software such as Malwarebytes or Avast is recommended to effectively protect your computer from malware.
To turn on Windows Security: https://support.microsoft.com/en-us/windows/stay-protected-with-windows-security-2ae0363d-0ada-c064-8b56-6a39afb6a963
macOS: Malwarebytes or Avast
Malwarebytes
Malwarebytes free download comes with a 14-day trial of the premium version with automatic (real-time) virus and malware protection. After 14 days, the trial reverts to a limited disinfection scanner.
To download Malwarebytes for macOS: https://www.malwarebytes.com/mac
Avast
Avast Free Antivirus detects and blocks all types of malware in real-time to prevent them from infecting your computer. At the same time, it scans your computer before the malware can do real damage. However, the free version doesn’t protect against ransomware.
To download Avast for macOS: https://www.avast.com/en-my/free-antivirus-download#mac
To stop data sharing in Avast: https://www.digitaltrends.com/computing/how-to-stop-avast-antivirus-from-selling-your-private-data/