Malicious Software Removal Tool
freely distributed virus removal tool developed by Microsoft for the Microsoft Windows operating system
Microsoft Windows Malicious Software Removal Tool (MRT) is a freeware second-opinion malware scanner that Microsoft's Windows Update downloads and runs on Windows computers each month, independent of the installed antivirus software. First released on January 13, 2005, MRT does not offer real-time protection. It scans its host computer for specific, widespread malware, and tries to eliminate the infection. Outside its monthly deployment schedule, it can be separately downloaded from Microsoft.
Availability
Since January 13, 2005, Microsoft has released an updated version of the tool every second Tuesday of every month (commonly called "Patch Tuesday") through Windows Update, at which point it runs once automatically in the background and reports if malicious software is found. The tool is also available as a standalone download.
Since support for Windows 2000 ended on July 13, 2010, Microsoft stopped distributing the tool to Windows 2000 users via Windows Update. The last version of the tool that could run on Windows 2000 was 4.20, released on May 14, 2013. Starting with version 5.1, released on June 11, 2013, support for Windows 2000 was dropped altogether. Although Windows XP support ended on April 8, 2014, updates for the Windows XP version of the Malicious Software Removal Tool would be provided until August, 2016; version 5.39.
The public source identifies “Malicious Software Removal Tool” as freely distributed virus removal tool developed by Microsoft for the Microsoft Windows operating system. This brief keeps that definition visible, then builds a research path around Malicious, Software and Removal.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Sep 9, 2026. The linked authority identifier is Q1259297. 1 of 2 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 2005, 2000, 2010 and 2013.
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This entry incorporates text from “Malicious Software Removal Tool” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.