How to remove a virus from a Mac
The bad news is that Macs are not “virus-proof” in fact they’ve never been “virus-proof”. It is fair to say that, up until now, there have been fewer viruses for Macs (and iOS devices) than for PCs (and indeed Android devices), however, as the saying goes, that was then and this is now.
Now, viruses are not usually about causing damage the devices, like they were in the old days, they’re about stealing data. Macs are premium devices and therefore the personal data of those who own them is likely to have a premium value. This means that there are already a number of nasties for Macs currently doing the rounds and probably more to come.
With that in mind, here is a guide as to how to remove a virus from a Mac.
First of all, do some basic troubleshooting to see if the problem could lie elsewhere
Even though Macs are premium devices they can have their performance issues just like Windows PCs. Just like with Windows PCs an awful lot of these issues can be solved by a simple reboot and if that doesn’t work, check your Activity Monitor to see if there is a specific program gobbling up your device's resources and if so kill it.
If that doesn’t work try removing all peripherals except the keyboard and mouse and rebooting again, if your computer then works fine, then it’s likely there’s a problem with a peripheral and you’ll have to use a process of elimination to work out which one it is (probably the last one you installed or updated).
Your last throw of the dice is to try a Safe Boot and, if it succeeds, do a standard reboot. It may sound odd, but it’s quite impressive how many issues that can solve.
Then check your browser extensions
If you do all this and get nowhere, then you could have a virus. It isn’t 100% guaranteed, but at this point it’s a serious probability. Your first step is to go through your browser extensions and look for trouble there.
Safari - Safari>Extensions
Chrome - Three-line (hamburger) menu (at the top right)>More Tools>Extensions
Firefox - Three-line (hamburger) menu (at the top right)>Add-ons>Extensions
These days, the most prudent approach is to decide whether you actually need a specific browser extension and if you can’t actively justify keeping it (some are genuinely useful), then get rid of it. This can be a tedious activity, especially if you haven’t done it for a while (or at all) and even more so if you use more than one browser (because you’ll have to check each one), but it can not only get rid of malicious extensions but generally improve your Mac’s performance. Once you’ve finished, reboot and see if you still have a problem.
Try downloading and running an antivirus.
One of three things will happen here.
You’ll be able to download and run an antivirus and it will solve your problem.
You’ll be able to download and run an antivirus and it won’t solve your problem
You’ll not be able to download and run an antivirus.
In scenario two, you may not have a virus and you’ll have to go back to your regular troubleshooting. In scenario three, you probably do have a virus and it’s sophisticated enough to try to protect itself against antivirus programs so you’re going to have to look for it manually. There are three places you need to check:
Your applications folder
Your ~/Library folder
Your main library folder
Check all your apps, plus your Application Support, Launch Agents and Launch Daemons
Sadly virus creators tend not to label their malware so that it can be identified easily, but your virus is probably amongst your more recent installs.
Try escaping the trap
If none of this works, then you have two fairly drastic options. One is to restore to a point before the virus hit, which will get rid of it but at the cost of losing any real files created since then. In theory you can restore them but you may restore the virus as well.
The other is to cross your fingers and hope that the virus is linked to a profile in which case creating a new profile should get around it and again, in theory, you can restore your files, although, as previously mentioned, this does have some degree of risk.
Protect yourself from this happening again
It may have been a painful experience, but if you head to this link you can save yourself the pain of having to go through this process again!