MRT is an anti-malware utility that checks a PC for infection by specific, prevalent malicious software and helps to remove the infection if it is found. The version of the tool delivered by Microsoft Update and Windows Update runs in the background and then reports if a malware infection is found. Microsoft will release an updated version of this tool on the second Tuesday of each month. It is set to automatically execute when any user logs into Windows (through the local user run registry setting) with the name ‘MRT’.