To answer your question, you don't but you can get Kaspersky from the Geek squad as extra protection to be safe or Norton offers a Mac protection system. Mac does not have windows. Its the software Windows that is subject to viruses and Malware from Microsoft. Not having Windows, Macs are not, but you can get Malware, or so I am told. I personally have never got malware or anything remotely damaging and I don't know anyone that owns a Mac that has but to be sure I run the Kaspersky as it came free when I bought the Mac.