Microsoft Windows malicious software removal tool

I have taken on this tool from the update site and from the site it says
From


http://support.microsoft.com/kb/890830

The Microsoft Windows Malicious Software Removal Tool helps remove malicious software from your computers that are running Windows 8, Windows Server 2012, Windows 7, Windows Vista, Windows Server 2003, Windows Server 2008, or Windows XP.

Microsoft releases a new version of the Microsoft Malicious Software Removal Tool every month. After you download the tool, the tool runs one time to check your computer for infection by specific prevalent malicious software (including Blaster, Sasser, and Mydoom) and helps remove any infection it finds.

This article contains information about how the tool differs from an antivirus product, how you can download and run the tool, and what happens when the tool finds malicious software on your computer. The advanced user section includes information for the IT administrator and additional information about how to manage and run the Malicious Software Removal Tool.

How do we know when the tool runs , how long it takes to run and what if anything it does with any problems it finds? I have yet to 'see' or be aware that it is running and do not know how long the scan may take

Can anyone advise please?

P;3, the tool installs right along with Windows Updates and runs immediately. I've not actually timed it, but it's pretty fast and efficient, and not something you need to worry about... it's all over and done with before your machine reboots itself. If the tool should find a problem, it will notify you and give you instructions if there is something you need to do.

To add to NonSuch's reply... the tool is updated frequently but usually runs with each Patch Tuesday "release".
So the scan takes place once a month, automatically.