Microsoft Defender Antivirus

Microsoft Defender Antivirus
Other namesWindows Defender Windows Security
Original authorMicrosoft
DeveloperMicrosoft
Stable release(s) [±]
PlatformMay 2026 Update (4.18.26050.15) / June 22, 2026 (2026-06-22)
Windows appFebruary 2026 Update (102.2602.23002) / June 3, 2026 (2026-06-03)
Android1.0.9014.0101 / June 19, 2026 (2026-06-19)
iOS1.1.7802.0101 / June 11, 2026 (2026-06-11)
Operating system
PlatformWindows
PredecessorMicrosoft Security Essentials
TypeAntivirus software, personal firewall, parental control, intrusion prevention, email filtering and anti-phishing
LicenseProprietary

Microsoft Defender Antivirus (formerly Windows Defender) is an antivirus software component for Microsoft Windows and mobile. It was first released as a downloadable free anti-spyware program for Windows XP and was shipped with Windows Vista and Windows 7. It has evolved into a full antivirus program, replacing Microsoft Security Essentials in downloadable genuine copies of Windows XP to Windows 7.

In March 2019, Microsoft announced Microsoft Defender ATP for Mac for business customers to protect their Mac devices from attacks on a corporate network, and a year later, to expand protection for mobile devices, it announced Microsoft Defender ATP for Android and iOS devices, which incorporates Microsoft SmartScreen, a firewall, and malware scanning. The mobile version of Microsoft Defender also includes a feature to block access to corporate data if it detects a malicious app is installed.