How To Remove A Virus From Your Mac

With the Flashback virus and its variants on the loose, there’s been a welcome focus on Mac security. But most of the instructions you’ll find for removing a virus are written for Windows. Here is how to remove a virus from a Mac.

First, you’ll want to read this article I wrote on What To Do If Your Computer Is Hacked, because much of the same advice applies here. Then…

Step 0: Install Mac Antivirus
The best protection is prevention, and antivirus software is as mandatory for Macs as it is for PCs. Apple’s built-in defenses are not enough. Here are my recommendations on Mac antivirus. My two favorites are Sophos and Intego. The freebies are fine but honestly, a solid security software suite is one of the best investments you can make for your computer.



Step 1: Scan For Viruses
Use your antivirus program to scan your Mac for viruses. Be sure to include any external hard drives or other volumes. If you are sharing drives from other Macs, it’s much faster to scan on the local Mac than scanning across the network.

Remember, it’s not just Mac viruses you’re worried about. Macs can’t be infected by PC viruses, but they can and will transmit them, to the displeasure of your Windows friends. Please be a kind neighbor and make sure your own house is tidy.

Step 2: Do A Second Scan
It’s always a good idea to get a second opinion by scanning with a different program. Select an alternate from above, but don’t try to run both at the same time or they’ll step on each other’s toes.

Step 3: Remove Viruses
In What To Do If Your Computer Is Hacked I wrote:

Your computer could have been infiltrated by a virus, a worm, a Trojan horse, a keylogger, a rootkit, scareware, malware, adware… These are all different types of attacks with different purposes, meaning there are greater and lesser degrees of infection.

Same thing applies to your Mac. Some viruses are just junky adware and easily removed. Others are nefarious keyloggers that embed themselves deep down in your system where no one will find them. Of course you don’t want any viruses on your computer, but some are worse than others.

Use your antivirus tool(s) for removal. Macs tend to clean up quite a bit better than PCs after infection, so in my experience reinstall isn’t required nearly as often. But be careful if you do a Web search for removal tools for specific viruses. Thanks to poisoned search engine results, a search for “Flashback removal tool” returns links to the virus itself!

Step 4: Secure Your Mac
If you’ve gotten this far, in all likelihood the viruses are gone. However, there’s no way to guarantee that. As I wrote in the same article

There is no way to confirm if a computer is free of viruses. I don’t care what any virus removal tool says. You can be 99% confident, but not 100%. When in doubt, reformat. It’s a pain but better than having a computer that keeps reinfecting itself. Remember, a virus can regenerate if even the tiniest portion of itself is left behind.

Assuming you’d rather not go through all that again, go back to Step 0 and make sure your Mac has proper antivirus installed. Then move on to Step 5…

Step 5: Follow Good Security Rules
The best software in the world won’t protect you if a wily cybercriminal can trick you into clicking something you shouldn’t. All that good advice about Windows security applies just as much to you, so watch out for Facebook scams, phishing emails, phony login pages and all the rest of it. If the idea of that daunts you, don’t worry. Just follow Tech Tips via email, Web and Twitter, and I’ll keep you in the know.

Some related Tech Tips articles you might find useful:

Questions about Mac security? Ask in the comments!

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