What to do if you think your Mac has a virus

If you are worried you have some kind of malware or virus on your Mac, we are here to help you figure out what’s going on and, if necessary, clean up the damage and get rid of a Mac virus – all for free. A lot of the websites offering advice on Mac malware removal are companies trying to sell your anti-virus solutions, which makes their tips somewhat biased, but here you can expect impartial advice.

We’ll cover how to check for a virus and how to remove malware from your Mac, getting rid of any viruses that might be lurking. We’ll also explain why it’s probably not a virus thanks to Apple’s stringent protections in macOS, but, if it is, we’ll let you know about the free and cheap options that can protect your Mac from malware.

Note that in this article we are going to be mixing and matching the terms malware and virus, but they are actually separate concepts. Malware tends to take the form of apps that pretend to do one thing, but actually do something nefarious, such as steal data. Viruses are small discrete bits of code that get onto your system somehow and are designed to be invisible. There are also other threats, such as ransomware and adware, and other phishing attempts, where an attempt is made to extract information that can be used to obtain money from you.

We’ll address how to detect and get rid of these types of malware on your Mac in this article.

We also recommend you read our best Mac security tips and our roundup of the best Mac antivirus apps, in which we currently recommend Intego as our top choice.

How to tell if your Mac has a virus

If your Mac has suddenly become very slow and laggy, started regularly crashing or showing error messages, and the sound of your fans whirring keeps you company, you may be suspicious that you have picked up some Mac malware. Another sign is the sudden appearance of annoying pop-up windows or extra toolbars and applications you don’t remember installing. These are all signs that you might have a virus on your Mac.

It’s not necessarily the case that a virus is to blame though. Mac malware is incredibly rare – Mac viruses do exist, in fact, there have been a few notable malware and virus reports in recent years, but there are a few reasons why Mac viruses don’t tend to take hold. One is the stringent protections Apple builds into macOS, another is the fact that it is exceptionally difficult for a virus to propagate itself and spread to other Macs, see: Why Macs are more secure than Windows PCs.

Signs your Mac has a virus

Here are some of the symptoms of malware or viruses you might watch out for:

• Your Mac suddenly becomes sluggish or laggy in everyday use, as if there’s some software running in the background chewing up resources.
• You find a new toolbar in your browser that you didn’t install. Typically these toolbars claim to make it easier to search or shop.
• You find any web searches are unexpectedly redirected away from your usual search engine to some site you’ve never heard of (or the results appear on a page that’s faked up to look like your usual search engine).
• All web pages are overlaid with adverts – even those where you don’t expect to see adverts, such as Wikipedia.
• Going to your favorite sites doesn’t always work, as if something is randomly redirecting you to spam advertising pages.
• Advertising windows pop up on your desktop, seemingly unconnected with any browsing you’re doing or any program that’s running.

If you get any of these symptoms then don’t panic: they don’t necessarily mean you have a malware or virus infection on your Mac. There are a thousand reasons why a Mac might run slowly.

How to check for viruses on a Mac

If having read the above you are sure that you have a virus or some other form of malware on your Mac then this tutorial should help you address the problem, read on for a guide on what to do if your Mac has a virus, starting off with how to scan your Mac for viruses.

Here’s one thing you definitely shouldn’t do if you think your Mac is infected with malware: don’t Google a description of the problem and install the first thing you find that claims to be able to fix things. Sadly, a lot of software that claims to be able to fix Macs is malware itself or is simply fake and designed only to make you part with money. These apps can look incredibly convincing and professional, so beware.

Fake antivirus apps like MacDefender (see image above), which hit the headlines a few years ago, might look the part but are actually malware in disguise.

If you think there is a virus, or some other threat, on your Mac, then there are a few things you can do, we’ll run through your options below. 

How to remove malware from a Mac for free

Using software to run a virus scan on your Mac is the easiest option. Luckily there are lots of apps offering to scan your Mac for viruses–some for free.

One option is the free-of-charge Bitdefender Virus Scanner. If you are willing to spend a little cash then the paid-for version of Bitdefender ($39.99/£29.99) is worth consideration. Read our review of the free Bitdefender Virus Scanner and our review of Bitdefender Antivirus for Mac.

Here’s how you can use the free Bitdefender Virus Scanner to search and remove viruses for free:

1. Open the Bitdefender Virus Scanner.
2. Click the Update Definitions button. 
3. Once that’s completed click the Deep Scan button.
4. Follow the instructions to allow the app full access to your Mac’s hard disk.

Another free option is AVG Antivirus for Mac. It’s basic, but protects you from viruses, spyware, and malware. You might also like to try Avira Free Security for Mac, which offers some features for free, although most require a paid subscription. Read our review of AVG AntiVirus for Mac.

Here are our favorite free options for detecting and removing malware.

Best Free Mac malware apps

These are the best free Mac Antivirus apps we have reviewed. These may help in an emergency, but for the best protection you may need to pay for a more complete solution, in which case, any of the top picks in our roundup of the best Mac antivirus apps will be able to scan for and remove a virus from your Mac – and the benefit of installing one of these should be that you never get caught out again.

To get the best value for a Mac antivirus app check out the Best Antivirus for Mac deals this month.

Another option is a Mac Cleaner like CleanMyMac X, which offers a virus scan among other features. This option costs $34.95/£29.95 a year right now (RRP: $39.95/£34.95), but it is one of our go-to utilities for doing various jobs on the Mac, such as deleting unnecessary files to make space. Here’s how we used CleamMyMac X to check for viruses.

1. Open CleanMyMac.
2. Click Smart Scan.
3. Wait while it scans. The results of the scan can be found in the Protection section.
4. Click Remove to get rid of any malware.

How to remove malware from your Mac without antivirus software

Using an antivirus app is a great option because it will scan your Mac for viruses and then remove them. But you don’t necessarily need to use a virus scanner to identify and remove viruses on your Mac.

Apple already scans your Mac for viruses. As we explain in how Apple checks your Mac for viruses Apple includes antivirus software in macOS that monitors your Mac for malware, blocks malware, and removes it if necessary.

Even with these protections (which do depend somewhat on the age of your Mac and the version of macOS you are running), there are still some ways to clean a virus from your Mac manually.

You may be wondering if you need to wipe your Mac to remove the virus, or indeed if wiping your Mac will completely remove the virus. It’s possible that you won’t have to go that far–try these steps to clean things up:

What to do if your Mac has a virus

In addition to the above, there are a few other things you should do to protect yourself if you think you might have been infected with Mac malware–before and after the virus is removed. 

1. Stay offline

While you think you are infected you should stay offline as much as possible. Try and turn off your internet connection by either clicking the Wi-Fi icon in the menu back and selecting Turn Wi-Fi Off, or disconnecting the Ethernet cable if you’re using a wired network.

If possible, keep your internet connection turned off until you’re sure the infection has been cleaned up. This will prevent any more of your data being sent to a malware server. (If you need to download cleanup tools then this obviously might not be possible.)

2. Use safe mode

Boot your Mac up in Safe mode – this should at least stop the malware from loading at start up.

3. Don’t use any passwords – and change them as soon as you can

From the moment you suspect you have a virus you shouldn’t type any passwords or login details in case a hidden keylogger is running. This is a very common component of malware.

Beware that many keylogger-based malware or viruses also periodically secretly take screenshots, so be careful not to expose any passwords by copying and pasting from a document, for example, or by clicking the Show Password box that sometimes appears within dialog boxes.

Once you are free of the virus you should change all your passwords, and we really do mean all of them – including those for websites, cloud services, apps, and so on.

4. Cancel bank and credit cards

If you handed over money at any point for the malware – such as if you paid for what appeared to be a legitimate antivirus app, for example – then contact your credit card company or bank immediately and explain the situation. This is less about getting a refund, although that might be possible. It’s more about ensuring your credit card details aren’t used anywhere else.

Even if no money has changed hands you should inform your bank or financial institutions of the infection and seek their advice on how to proceed. Often at the very least, they make a note on your account for operatives to be extra vigilant should anybody try to access in future but they may issue you with new details.

Hopefully, these tips will help you remove malware from your Mac, now read How to protect your Mac against attack and disaster to avoid getting infected again.