The Microsoft Windows Malicious Software Removal Tool checks Windows Vista, Windows XP, Windows 2000, and Windows Server 2003 computers for and helps remove infections by specific, prevalent malicious software—including Blaster, Sasser, and Mydoom. When the detection and removal process is complete, the tool displays a report describing the outcome, including which, if any, malicious software was detected and removed. The tool creates a log file named mrt.log in the %WINDIR%debug folder.

This tool will help to remove specific, prevalent malicious software from infected systems. Because computers can appear to function normally when infected, Microsoft advises you to run this tool even if your computer seems to be fine. In addition to using this tool, you should use an up-to-date antivirus product to help protect your computer from other malicious software.

This tool is not a replacement for an anti-virus product. To help protect your computer, you should use an anti-virus product.

The user must be an administrator to run this tool. This tool will not run on any version of Windows 98, Windows ME, or Windows NT 4.0.