Microsoft Security Essentials is a free anti-malware tool available for Microsoft’s Windows Vista and Windows 7 operating systems that is designed to protect computers from viruses, spyware and other forms of malware.
While Microsoft continues to offer Microsoft Security Essentials for Windows Vista and Windows 7, the tool cannot be used on Windows 8 or newer OSes. Instead, the company includes a successor to Security Essentials called Windows Defender that is built into the operating system.
And while Microsoft initially offered support for Microsoft Security Essentials on Windows XP, the company has since discontinued supporting the tool on this operating system.
Microsoft Security Essentials vs. Windows Defender
Both Microsoft Security Essentials and Windows Defender offer real-time protection against viruses, rootkits, spyware and other malicious software to go along with online and offline system scanning and cleaning.
Microsoft Security Essentials does, however, lack Windows Defender’s enhanced protection against rootkits and bootkits.