Malicious Software Removal Tool

Published: January 11, 2005 | Updated: October 09, 2006

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The Microsoft Windows Malicious Software Removal Tool checks computers running Windows XP, Windows 2000, and Windows Server 2003 for infections by specific, prevalent malicious software—including Blaster, Sasser, and Mydoom—and helps remove any infection found. 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.

Microsoft releases an updated version of this tool on the second Tuesday of each month, and as needed to respond to security incidents. The tool is available from Microsoft Update, Windows Update and the Microsoft Download Center.

Note  The version of the tool delivered by Microsoft Update and Windows Update runs in the background and then reports if an infection is found. If you would like to run this tool more than once a month, use the version on this Web page or install the version that is available in the Download Center.

Because computers can appear to function normally when infected, Microsoft advises you to run this tool even if your computer seems to be fine. You should also use up-to-date antivirus software to help protect your computer from other malicious software.

To download the latest version of this tool, please visit the Microsoft Download Center.

You can also perform an online scan of your computer using the Windows Live OneCare safety scanner.

Run an Online Scan of Your PC for Malicious Software

If you would like to scan your computer for malicious and potentially unwanted software from a website, please use the Safety iconWindows Live OneCare safety scanner.

Windows Live OneCare safety scanner is an online service that lets you scan your computer to help protect, clean, and keep it running at its best. Use our free protection scan to check for and remove viruses, spyware, and other potentially unwanted software and to find vulnerabilities in your Internet connection.

Learn How to Protect Your PC

To help protect your computer against a wide variety of security threats, see Protect Your PC.

Technical Assistance

Contact your antivirus vendor for assistance with identifying or removing virus or worm infections. If you need more help with virus-related issues, contact Microsoft Product Support Services.

  • For support within the United States and Canada, call toll-free (866) PCSAFETY (727-2338).
  • For support outside the United States and Canada, visit the Product Support Services Web page.

New Additions

We have added detection and cleaning capabilities for the following malicious software:




See the complete list of malicious software cleaned by this tool.