Microsoft Security Essentials (MSE) is an antivirus software (AV) product that provides protection against different types of malware such as computer viruses, spyware, rootkits and Trojan horses. It runs on Windows XP, Windows Vista and Windows 7, but not on Windows 8, which has a built-in AV component. The license agreement allows home users and small businesses to install and use the product free of charge. It replaces Windows Live OneCare, a discontinued commercial subscription-based AV service, and the free Windows Defender, which until Windows 8 only protected users from adware and spyware.
FeaturesMicrosoft Security Essentials is an antivirus software (AV) product that fights malware (malicious software), including computer viruses, spyware, Trojan horses and rootkits. The software runs on Windows XP, Windows Vista and Windows 7. It replaces Windows Live OneCare, a discontinued commercial subscription-based AV service, and the free Windows Defender, which until Windows 8 only protected users from adware and spyware. It automatically checks for and downloads the virus definitions it relies on from Microsoft Update, a web-based software service updated three times a day. Users may alternatively download the updates manually from the Microsoft Security Portal website. On 30 September 2011, a faulty definition update caused the product to incorrectly tag Google Chrome as malware. The issue was resolved within three hours.
MSE is built upon the same foundation as other Microsoft security products; all use the same virus definitions and anti-malware engine, known as Microsoft Malware Protection Engine (MSMPENG). It lacks the personal firewall of OneCare or the centralized management features of Forefront Endpoint Protection.
MSE provides real-time protection, constantly monitoring activities on the computer and scanning new files as they are downloaded or created. It disables detected threats and prompts for user input on how to deal with them. If no response is received within ten minutes, suspected threats are handled according to the default actions defined in the application's settings. Depending on those settings, it may also create System Restore checkpoints before removing the detected malware. As a part of real-time protection, by default, MSE reports all suspicious behaviors of monitored programs to Microsoft Active Protection Service (MAPS, originally Microsoft SpyNet), a web-based service. If the report matches a newly discovered malware threat with an unreleased virus definition, the new definition is downloaded to remove the threat.
Hardware requirements for the product depend on the operating system. On a computer with Windows XP, it requires at least a 500 MHz processor and 256 MB of RAM. On a system running Windows Vista or Windows 7, it requires a 1 GHz processor and 1 GB of RAM. It also needs a computer monitor with a display resolution of at least 800 × 600 pixels, 200 MB of free hard disk space and an Internet