I have just completed the downloading of the latest version of iTunes. This took ~90 mins as opposed to ~10 minds with my previous security software. The main culprit seemed to be mcshield.exe which took 80% - 90% of the CPU (sometimes even more) at various stages of the installation. This is not the first time this file has brought my computer to its knees. I am very disappointed and frustrated and question the functionality and design of this utility.