OS X Concepts for Windows Users: Do I Need to Run an Antivirus in OS X?

Continuing my article series about helping Windows users work with Macs and OS X, I figured that now would be a good time to talk about a huge question that PC users face when moving to (or at least visiting) the Mac platform:  Do I Need to Run Antivirus Software on my Mac?  After doing lots of reading and discussing, the answer I’ve come to is:  (at least as of mid-2011)…not really.

OS X is Fundamentally Different from Windows
OS X is built on UNIX, and therefore is inherently much more secure than a Windows system.  Without getting into the nitty-gritty, UNIX does a much better job of security out of the box as opposed to Windows.  Windows 7, however, has made great strides in improving security but still REQUIRES antivirus software (and anti malware software, as well).  So while I wouldn’t dare go on the internet with a Windows system without using security software, I’d browse freely on the internet with a Mac and OS X.

Are there Viruses for the Mac?
Well, kind of.  Generally speaking viruses and malware that’s written for Windows won’t run on a Mac .  For the same reason that Photoshop for the PC won’t run on OS X, viruses written for Windows won’t run on a PC.   That being said, if you want to be super-cautious, you can run an antivirus program for OS X (see below).

Who Should Run an Antivirus on OS X?
If you walk into the Apple Store and ask about viruses on the Mac they’ll say, “You run Windows, right?”.  Ask the majority of Mac users and they will give you a similar funny look and tell you that they don’t run antivirus.  Coming from Windows, however, running ANY computer without some kind of antivirus software gives we PC users the feeling that we left the stove on — it’s dangerous and we wouldn’t do it.

The one group of people who I would recommend running an antivirus software on their Macs would be people who are running Windows in Parallels or Fusion on OS X. Naturally you will have to run antivirus on the Windows virtual machine, and while the odds of anything “crossing-over” from Windows to OS X is extremely rare, running an antivirus will make you sleep better at night (at least it made me sleep better).

So for the run of the mill Mac, you are pretty safe out of the box.  But if you are running a virtual Windows machine (or if you spend a lot of time on websites that may have high risks for acquiring viruses), then I’d strongly consider running antivirus software.

What is the Best Antivirus Software to Use on the Mac and OS X?
Currently there are a few software programs out there for Mac users, the most notable commercial one being Norton.  That being said, the one that I’d recommend at this time is ClamAV.  ClamAV is a free (yes, FREE) n antivirus program for OS X that does a good job and (at least on my test system) has a minimal resource footprint (we PC users know all-too-well about antivirus program like Norton sucking the life out of a PC with all it’s loading, and scanning, and memory eating).

ClamAV itself needs to be compiled, but there is a pre-compiled (e.g. you just run it) available and this program is called ClamXAV.  ClamXAV can be downloaded from the link in the previous sentence, or can be downloaded at the App Store.

Note that there is a difference between the  version you download and the App Store version.  Due to certain App Store limitations, the  App Store version cannot “run in the background.”  So if you are running the App Store version you will simply need to run the program when you want to scan (or just leave it on and then scan on a regular basis).  Currently I leave the program running and I scan once per week.

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