You can change the antivirus program's settings to best suit your security needs. If you've upgraded to Windows 10, you might notice the inclusion of a program called Microsoft Defender Antivirus. Here's the lowdown on what the program is, how to make sure it's enabled on your computer, and how to change its settings. What to know about Microsoft Defender Antivirus, formerly known as Windows Defender Microsoft Defender Antivirus, formerly known as Windows Defender, is an antivirus protection program that's included with Windows 10. Unlike other antivirus programs like McAfee, Microsoft Defender is free and doesn't require any additional installation. Microsoft Defender's features include automatically backing up files to OneDrive, expansive parental control settings, and the elimination of any need for passwords, which have been replaced by face recognition and fingerprint technology.