Should I install anti-virus software on my Mac?

I’ve lost count of the times I’ve been asked this question, especially from Windows users switching to the Mac. There’s a short answer. Probably. I tend to scan anything I download prior to installing it and anything Office documents I get.

Whilst OS X has very very few security threats that are currently being exploited, unlike Windows which has tens of thousands, that doesn’t mean to say that you should be cautious. I know at least two of my clients who had bizarre slowness uses the Internet, which turned out to be cases of DNS Changer.

Most security exploits on the Mac come from people installing software that has had Trojans added to the payload. Often they originate in dodgy software they’ve blagged off the internet, or from strange video codecs they’ve installed to watch online video. So follow a few simple rules.

1. Only trust software that you know exactly where it has come from.
2. Assume that any attachments sent via are suspicious
3. If you don’t need it, don’t install it.
4. Dodgy software your mate gave you is all well and good, but don’t trust it.

Should I buy anti-virus software for my Mac?

God no! If anyone tries to sell you Intego VirusBarrier, Norton Internet Security or Sophos Anti-virus they probably just want your money, rather than what’s best for you. ClamAV for OS X is free, stable and unobtrusive. Just put it in your Dock and drag anything suspicious onto it to initiate a scan. Just make sure you keep the virus definitions up to date.

I run Parallels or VMWare Fusion on my Mac – should I use anti-virus software?

You should very definitely have it installed in the Virtual machine if you care about the data in it, but it poses little threat to you Mac unless you setup shared folders. If the Virtual machine can access folders on your Mac, then that data is vulnerable, so be doubly cautious if this sounds like you.