Recently a gentleman gave a presentation at a PC Club in Prescott on installing the Avast Antivirus program. Although the presentation was oriented for PCs, most of his presentation applies to Macs as well. For your possible interest, I've included a link to his presentation. As a side note (and I've mentioned this previously), I use the free Avast AV program on my Mac and PC, and have done so for many years. For a free AV program, I think it is a fine program. Read about it here . Jim Hamm