that they suck 10. Does Virtual PC make my Mac more vulnerable to computer viruses? Windows running on a virtual machine is less susceptible to viruses than Windows running on a PC. It is unlikely that a virus will affect the Mac OS or Mac files, but in certain circumstances your virtual machine running Windows exposes you to the same security risks that users running Windows on a Windows-based computer face. To lower your risk, make sure you have always installed the latest Windows security patches and service releases. To learn how to keep Windows up-to-date, search Virtual PC Help for Windows updates.