Windows Malicious Software Removal Tool

What Windows Malicious Software Removal Tool is

Windows Malicious Software Removal Tool (MSRT) is a free Windows utility for finding and removing prevalent malware threats and reversing changes they made. It runs in the background through Windows Update when automatic updates are enabled, and Microsoft generally releases it monthly, usually on the second Tuesday. You can also download the standalone tool and run it on demand. Following a standalone scan, MSRT presents a report of the threats it found and removed and writes a log to %windir%\debug folder\mrt.log.

MSRT requires local administrator privileges. Its coverage focuses on prevalent malware families; Microsoft says it is not a replacement for full-fledged antimalware such as Windows Defender Antivirus. The download page lists Windows 10, Windows 11, Windows 7, Windows 8.1, and specified Windows Server releases as supported. The tool supports multiple languages and uses United States English if the operating system language is unsupported. The listed download is version 5.145, published September 11, 2026, with a file size of 84.0 MB. Microsoft provides IT administrator information covering command-line switches, deployment, covered malware families, and removal of the tool.

Who it suits

MSRT suits Windows users who want a free, periodic tool to find and remove prevalent malware, either through Windows Update or with a standalone scan. IT administrators can also use Microsoft's information on deployment and command-line switches.

Limits

MSRT targets prevalent malware families only and is not a replacement for full-fledged antimalware such as Windows Defender Antivirus. It requires local administrator privileges and is limited to Windows.

Getting started

1. Visit Microsoft's download page.
2. Use Windows Update with automatic updates enabled, or download the standalone tool.
3. Run the standalone tool on demand with local administrator privileges.
4. Review the scan report and, if needed, the log at %windir%\debug folder\mrt.log.

Verdict

Pick MSRT if you want a free Windows tool for periodic cleanup of prevalent malware, with background delivery or an on-demand standalone scan. Look elsewhere if you need full-fledged antimalware protection, since Microsoft explicitly says MSRT is not a replacement for it.