Q: The Malicious Software Removal Tool (MSRT) used to be available for download from the Microsoft website. It could scan Windows boxes for certain malware. Is MSRT still available for Windows Vista?

A: Yes, MSRT is still around in Vista. What few people know is that your computer automatically downloads and runs MSRT when you’ve enabled Automatic Updates. MSRT runs not only on Vista, but also on Windows Server 2003, Windows XP, and Windows 2000. MSRT can’t run on machines with older OSs.

When Automatic Updates are enabled, your computer automatically downloads and executes MSRT on a monthly basis. The tool always runs in quiet mode unless it finds an infection—if you aren’t notified of an infection, it means that MSRT hasn’t found any malicious software that needs your attention.

MSRT doesn’t use an installer. When it runs, it creates a randomly named temporary directory on the root drive of your computer. This directory contains several files, including the MSRT executable, Mrtstub.exe. This directory is automatically deleted after the tool finishes running or the next time that you start the computer.

The only trace of MSRT you can find on a computer is the MSRT log file. The results of the latest MSRT scan are always added to the mrt.log file, which is stored in a subfolder called Debug in your Windows directory. An example mrt.log is shown here:



If you want to run MSRT manually, you can download the tool from Microsoft. When you run the tool manually, you can select a scan type and MSRT will show the progress and results of the scan