MasterAntiVirus (also known as Master Anti Virus) is intrusive and annoying malware. It is not capable of doing much damage to a computer. However, MasterAntiVirus is promoted as anti-spyware; it’s dangerous because people may lose their money if they believe in this scam. Master Anti Virus is a fraudulent security tool. It loads intrusive pop-ups and falsified security alerts. Do not trust messages displayed by MasterAntiVirus! Although it is presented as a security tool, it is not capable of scanning a computer or detecting infections. Master Anti Virus spreads with help of trojans.

Source: http://www.2-viruses.com/remove-master-antivirus