Do I "Need" to Use Anti-Virus Software?

Question

A user in another forum asked me this question. I realize this is hardly a new topic, but below was my answer. I figured I would post it here and get your thoughts as well. Perhaps this and your comments will be helpful for others with the same question.
One question; I do not have an antivirus installed. Does a Mac need an antivirus installed? if yes, what would you recommend?
Does a Mac "need" antivirus software? Though this can be a controversial topic with some, my simple answer is "No". Personally, in the some 20 years I have been using Macs I have never installed an antivirus program. During that same time I have never been infected by a Mac-targeted virus/trojan/worm etc.
That is not to say that trojans and vulnerabilities have not existed. But the truth is, unlike PCs, Macs simply do not make good targets for these kinds of attacks. For the most part, for a Mac to become compromised a user has to permit it by lowering their defenses or manually installing some infected software package. On the other hand many PCs can become infected without any effort on the users part. Thus the need for every PC to be running antivirus software. After everything has been said and done, the truth is attacks on the Mac have simply not been very effective. Whereas, a PC virus can be spread worldwide within hours and days.
Macs also enjoy the benefit of being a less attractive target for hackers. If you are a virus designer, you want your product to have the most impact, and make headlines. As a result you are going to target the largest sector of the computing population - PCs. Additionally, most of the more recent attacks by hackers have been to establish what are called 'botnets'. These are large numbers of compromised PCs connected together via the internet, all controlled by one or more criminal entities. Most of these PC owners are unaware that their computers has been silently taken over to be used for gleaning information for identity theft or to distribute spam email worldwide. Since Macs are a completely different platform, and their numbers significantly fewer than PCs, it's simply not worth the effort to design software to include Macs in these botnets.
That doesn't mean that I do not observe safe computing practices. Think twice before downloading any file being offered by 3rd-party websites. If it is not from a known/trusted website then avoid it. Carefully, review emails you receive from unknown senders. Are there attachments you were not expecting to receive? DO NOT click on them. Avoid passing on chain emails of cute pictures, clever jokes, and interesting facts. These kinds of emails can actually be very effective ways for hackers to distribute hidden computer viruses because they know people can't resist passing on these kinds of email messages. In nearly every instance, I will read these kinds of emails, and then hit Delete.
Avoid advertising your primary email address to the world. That is, resist using your email address to fill-out contest forms or signing up for websites or various offers that are simply attempts at gleaning personal information. Guard your email address like you would any other personal information. If you must submit an email address to an unknown entity, use a special email address (or alias) set up just for these instances. Then when that email account becomes clogged with spam, close it and setup another one. But reserve your primary email address just for family, friends, & business use.
Finally, antivirus software for the Mac is notoriously problematic. At best, it simply slows your system down. At worst, it introduces points of failure and crashes that are simply not necessary. And such software often interferes with normal processes such as Time Machine backups, MobileMe syncing, and file transfers. Also, antivirus software can only protect you from 'known' threats. If there are no legitimate 'known' threats to the Mac right now, what are you protecting yourself against? If a genuinely virulent new virus/trojan suddenly appears among the Mac community, then you will either, buy antivirus software at that point, or already be infected, at which point you will buy antivirus software at that point. But running antivirus software now will not protect you against an unknown threat
Some will argue that, while the Mac itself is less likely to become infected, you should still run antivirus software as it is designed to catch PC viruses that you might pass on to PC users. That is a personal decision. However, my position is this, if I'm going to observe save computing practices, then I am unlikely to pass on any PC viruses to begin with. Why slow down my own system for the benefit of others if I'm unlikely to behave in a way that will compromise their computers?
So, again, while it is a personal choice, the above answer is why I, personally, do not run antivirus software at this time. Cheers!

Answer 1

Hi Glenn. I just wanted to let you know that your post in the subject line above helped me save the life of my wife's MacBook Pro (early 2008 15" Intel Core 2 Duo/Snow Leopard 10.6.2). The OS was messed up beyond repair - I believe it's due to the fact that her iPhoto library is on an external HD combined with her using iPhoto as her screen saver, which caused some sort of permissions anomaly that over time became irreparable. Not sure though, but the thing was practically unusable. In any case, thank you thank you thank you for how precise your explanation was - I followed it to the letter and lo and behold was able to wipe the drive, re-install Snow Leopard, and restore it from the Time Machine backup. So you should know that although you were writing at the time about Leopard, the exact same process worked perfectly for Snow Leopard as well. Thank you again!