When you run your Windows Updates every month you always see an entry for the ‘Windows Malicious Software Removal Tool’, but have you ever wondered what this actually does?

You can read the full details on Microsoft’s site, but in a nutshell this tool is a post-infection removal utility which means it only actually does something if prevalent malicious software is detected (in other words, it is not going to prevent an infection, only attempt to clean it up). When you run it from Windows Update, the scan takes place in quiet mode and you are only notified and prompted if something is found. No news is good news.

In addition to the Windows Update release, you can download the ‘full version’ of the Malicious Software Removal Tool which includes a graphical scanner. The full package scans for the same items as the Windows Update tool, but simply displays the results to you at the end. You can also view the log file produced by the Windows Update utility by viewing the file:

%WINDIR%\debug\mrt.log

For the most part, this file will just say “Scan done on [date] found 0 infections.”

All in all, the Malicious Software Removal Tool is nothing to get excited about, just an extra safeguard for your system.