Scanning Your Mac for Viruses: Why It’s Important

Mac Users Should Check for Viruses

In this article we do a case study on a recent Mac problem, give reasons why you should always start afresh with each new Mac you buy and in a larger sense why virus checking is more important for Mac users than other platforms, even though viruses are a less widespread problem.

Mac Viruses Are No Joke

We all know the jokes about Mac viruses, but we are staunchly “platform agnostic” around here. Recently one of our Macs began acting very strangely. It seemed to always be doing something when nothing was running. The first thought was a virus, and while investigation and virus scanning proved this was almost certainly not the case, the fact remained that something was horribly wrong.

It turned out in the end a legacy .ktext configuration file was more than likely to blame, running drivers for some now non-existent graphics tablet and scanner from a previous install which ate all of the free memory.

System extension cannot be used warning message.

We’ll get to the madness of cloning your old machine to a new one in a second because this problem raised a bigger question: the role of Mac users in the world of virus spreading.

Catching the Bug

For Mac users, viruses are less of a problem than users of other platforms (you know who we are referring to, right?), although they are possible and do actually happen. It’s a big mistake as a Mac user to ignore this because although viruses which affect the Mac by covert insertion are uncommon, many other threats exist which could paralyze or ruin your current installation. We recently covered removing the MacItNow adware, for example.

And while unaffected by PC virus threats, you can easily become a carrier for PC virus infections. Windows files cross your desk invisibly all the time, and it’s the right thing to do to scan and remove them before you pass them on, otherwise this could be potentially very bad news for your PC-using co-workers, family or friends.

In the recent repair of the Mac we mentioned above, for example, scanning revealed a couple of minor Mac threats but literally hundreds of PC viruses on the system. That’s alarming as hell.

Burn Them With Fire

There are a few free options which do very well to remove any Mac or PC threats from your machine. AVG, Avast and Bitdefender are the options we tried in purging this problem Mac.

Bitdefender free version is a scanner and goes through your files detailing any threats, pointing you to the problem files so you can delete them.

Bitdefender Virus Scanner for Mac.

AVG Free is a scanner and a shield program. You can explicitly scan your machine periodically for Mac and PC threats.

AVG AntiVirus for Mac.

The shield part means it stays resident even when you are not actually running the GUI and checks threats as they arise in real time.

Threats blocked by AVG AntiVirus.

Avast is similar to AVG in that it is a scanner and a shield, scanning your disk for threats manually but also staying resident to catch anomalies in real time. Like other resident virus checkers it won’t install unless potential threat collecting apps are closed:

Install Avast Mac Security app.

Like AVG, it gives you the option to scan for threats by presenting a front end GUI:

Ccan for threats via a front end GUI.

And manual scanning can take considerable time. A full system scan can take hours (note the time taken and percentage covered here in our problem Mac for example):

A full system scan can take hours.

You should do that at least once a month to be sure. And as with all virus software, make sure your virus definitions are fully updated before you do so. Once in place however, the day to day operation is handled by the shields:

Avast Mac Security Shields.

Note: something to look out for is that according to our tests, virus software sees other virus software from rival companies as a threat – this is probably not a marketing ploy but simply because they stay resident in memory. Don’t run more than one piece of virus software as you may end up crippling your installation of one or the other accidentally.

Two threats found.

Don’t Go Cloning Your Problems

Virus checking is a good thing, no question. But why is cloning your old machine to your new one using the Mac Transfer system such a bad idea in this regard?

Not only can you a) transfer lingering configuration problems from old software, but most importantly b) you run the risk of copying already resident PC viruses onto your new Mac ready for you to pass on to everyone you come into contact with digitally.

As a responsible user, you should always start afresh with a new machine. It is better to regularly back up your files than to clone the whole OS. It’s quicker to install individual software programs than it is to copy an entire 500Gb system disk, and you remove any performance killing configuration problems which may act like viruses.

Most importantly, you should check your system for viruses regularly using one of the software programs mentioned above.

Have you had any virus nightmares on the Mac? Let us know in the comments below.

Phil South
Phil South

Phil South has been writing about tech subjects for over 30 years. Starting out with Your Sinclair magazine in the 80s, and then MacUser and Computer Shopper. He's designed user interfaces for groundbreaking music software, been the technical editor on film making and visual effects books for Elsevier, and helped create the MTE YouTube Channel. He lives and works in South Wales, UK.

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