How to Know if Mac Has a Virus

The notion that Mac systems cannot get infected by malware is wrong and the last couple of years have proven that with the exponentially increasing numbers of malware infections for Mac systems. While it is still true that you are more likely to land a virus on a Windows computer than on a Mac, the people who use Mac machines definitely need to know how to keep their systems malware-free and how to spot any potential threats that may have entered their computers, which is why this article has been written.

How to check if Mac has a virus?

You can check if your Mac has a virus by looking out for potential infection symptoms and by paying attention to the system warnings of Mac’s built-in security features. You can also check if Mac has a virus by scanning it with third-party security software.

Here are some common malware red-flags for Mac:

  • Performance issues such as slow-downs and freezes.
  • Your web browser tabs are filled with ads that are superimposed over the page’s contents.
  • Applications starting without you having opened them.
  • Automatic installs of suspicious new software or updates.
  • Sudden restarts of the computer for seemingly no reason.
  • Frequent warnings from third-party software about viruses in your Mac, that prompt you to buy the software’s full version to remove the purported threat.
  • Weird new add-ons to your browser that you don’t remember installing.
If Mac Virus

How to check if your mac has a virus?

Noticing some of the above-mentioned symptoms doesn’t necessarily mean that your Mac has been infected. There could also be other issues causing these symptoms that aren’t related to malware. However, since there’s no way of knowing for sure just by looking at the symptoms, it’s best to not take any chances and check your Mac for malware using a reliable third-party security program. Also, even if the symptom isn’t caused by malware, you should still try to find the root of the issue in order to fix it. If you have been attacked by malware that is not in Mac’s databases, you will likely not get warned about the infection. However, you may still notice some signs of its presence.

Mac computers have several automated built-in security features that keep them safe from malware. They are designed to provide your computer with protection against most forms of software threats which is why Macs typically don’t require a third-party antivirus. However, it must be noted that these features don’t come with a user interface like antivirus programs do. In other words, you don’t get to use a centralized app through which you can control and customize your security settings, schedule scans, and so on. This means that you can’t start an actual malware scan on your Mac unless you are using a third-party antivirus or anti-malware tool. Nevertheless, if there’s malware on your Mac and the system security features detect it, you will be promptly notified. Below, we will break down what the different Mac security features do and what warning notifications you may get if they spot malware.


This security feature is similar to Windows Defender and it mainly keeps you protected against potentially malicious files you may download from the Internet and against insecure browser extensions. XProtect operates automatically and it will scan new data or extensions the moment you try to download/install them. If it determines that something may be unsafe, it will warn you that the file in question may damage your computer and it will advise you to move it to delete it. Below the warning box, you will be given the options to open the file, to cancel the warning window, or to move the unsafe file to Trash.

Note that XProtect can be bypassed if you download files using third-party software such as BitTorrent or BitComet. Also, XProtect only detects known malware using its database, meaning that it’s ineffective against zero-day attacks (i.e. threats that are new and are still not present in the database).


GateKeeper is a Mac feature that doesn’t allow unverified software to get installed on the computer. Verified are the apps that come from App Store or that have been created by verified developers who have been issued an Apple certificate. Additionally, apps need to be notarized by Apple to be deemed safe. If a given app doesn’t meet the safety requirements, you will get a warning from GateKeeper that the app may be unsafe. The type of warning may vary depending on which of the safety requirements aren’t met by the app. You may be warned that the application isn’t from the App Store, or that its developer isn’t verified. If the app hasn’t been notarized, the warning will tell you that it has been downloaded from the Internet and ask you if you are sure you want to open it. Depending on your GateKeeper settings, you may not be allowed to open applications that aren’t from the Store or that don’t come from verified developers.

MRT (Malware Removal Tool) 

This is the third security feature of Mac systems that we want to talk about and it runs automatically during OS updates. Similarly to XProtect, MRT uses a database and only detects malware that’s present in it. Against unknown threats, there’s not much MRT can do to keep your Mac safe. MRT also doesn’t have a user interface and it gives the same warnings as the other two features if it detects anything dangerous.

Checking Mac using third-party tools

With the increasing number of malware threats for Mac, many users have chosen to enhance their system’s protection using a third-party security tool. Generally, this is seen as a bad idea as most such programs are fake and do more harm than good. In fact, oftentimes Mac malware programs are disguised as antivirus/anti-malware tools and they show false positives to the users in attempts to get them to purchase the full version of the fake antivirus.

However, installing a legitimate Mac security tool that is actually reliable may greatly help you keep your computer safe and maybe even fend off zero-day attacks that cannot be handled by Mac’s built-in protection features. Therefore, if you are worried that your Mac may get attacked by malware or that it has already been infected by a zero-day virus that macOS can’t recognize, it might be a good idea to install a dependable security app and scan your system with it. 

What to do if Mac has a virus?

If your Mac has a virus and the system defenses haven’t been able to deal with it, you can try to deal with the malware manually. If your Mac has a virus, you can also use a trusted antivirus/anti-malware tool to remove the infection.

If you choose to manually deal with the threat, know that our site offers many articles dedicated to different Mac threats and we always try to cover the newest and most dangerous viruses for Mac, so you can search for the specific virus you are dealing with on our site and follow the removal guide provided there.

The second option is to use third-party software. As we mentioned above, you must be careful when choosing an antivirus/anti-malware tool for your Mac since many such programs are fake, and some may even be considered as malware. On the current page, you can find a reliable professional anti-malware program for Mac that we recommend to our readers so if you think you have a virus on your Mac and you can’t handle it on your own, our suggestion is to use that tool to deal with the problem.

However, you can also try to deal with a Mac virus by yourself by following our detailed removal guide for Mac.

How to protect my Mac?

There are numerous methods that you can apply in order to increase your Mac’s safety and make it less likely for you to experience malware infections. Here are some of the top tips that you should adhere to in order to keep your computer protected:

Don’t keep any suspicious extensions in the browser – low-quality extensions can make your browser slower, fill it with unsafe ads, and page-redirect you to hazardous sites. It is important to only keep browser extensions that you actually need and which are trusted and safe.

Keep your Firewall enabled

To check if the Firewall is on, go to System Preferences > Security & Privacy and open the Firewall tab. See if the Firewall is enabled and if it isn’t, enable it.

Practice safe browsing

This is one of the most important safety tips – if you want to keep your system safe, you shouldn’t visit any sketchy sites, download low-quality or pirated software, click on random ads or open spam messages (or their attachments). Carelessness while browsing is one of the most common reasons people get attacked by malware.

Trust Mac’s built-in defenses

We already told you about the security features that Mac has and the warnings they could give you if they spot something potentially hazardous. A good rule of thumb is to trust those warnings and to follow the course of action they suggest unless you are absolutely sure that the file they warn you against is perfectly safe.

Backup important data

If you don’t want to lose any valuable files in case of a malware infection, be sure to back them up on external devices. If you think your Mac may have been infected, don’t connect the backups until the malware gets removed from the system.

About the author

Brandon Skies

Brandon is a researcher and content creator in the fields of cyber-security and virtual privacy. Years of experience enable him to provide readers with important information and adequate solutions for the latest software and malware problems.

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