The fastest way to check your Mac for viruses
macOS includes a built-in malware scanner called Xprotect that runs automatically in the background. It scans files when they download and when you open applications, and it updates its virus definitions daily without you doing anything. If Xprotect detects something, it quarantines the file and shows you a notification.
For a manual scan beyond what Xprotect does automatically, your best option is Malwarebytes for Mac, which you download and run on demand. It scans your entire system for threats that Xprotect might miss, takes about 10 to 20 minutes depending on how much is on your Mac, and shows you what it found. The free version scans and removes threats; the paid version adds real-time monitoring.
If you think your Mac has a specific problem — unusual slowness, pop-ups you did not click, or apps you do not remember installing — start with Malwarebytes. If you just want to verify that nothing obvious is wrong, Xprotect is already doing that work for you.
Key Takeaways
- macOS Xprotect scans files automatically when they download and when you open apps, so you do not need to do anything to get basic protection.
- Malwarebytes for Mac is the most widely used manual scanner and finds threats Xprotect sometimes misses, with a free version that removes what it finds.
- Activity Monitor shows you what programs are running right now, which helps you spot unfamiliar apps that might be malware.
- Viruses that lock your Mac or demand payment are rare on macOS, but adware that shows unwanted ads or changes your browser is common and removable.
- The best protection is not opening files from unknown senders, not downloading from untrusted websites, and keeping macOS itself updated.
How to run Malwarebytes on your Mac
Go to malwarebytes.com, click the download button, and save the installer to your Downloads folder. Double-click the installer, follow the prompts to install it, and then open Malwarebytes from your Applications folder. Click the "Scan" button and wait for it to finish — it will show you a list of anything it found, with options to remove each item.
Malwarebytes is not made by Apple, so macOS will ask you to confirm you trust it. Click "Open" when prompted. The scan is thorough but takes time; do not interrupt it or close your Mac's lid while it runs.
After the scan finishes, Malwarebytes shows you a report. If it found nothing, your Mac is clean. If it found something, click "Remove" to delete it. You may need to restart your Mac for the removal to take full effect.
What to look for in Activity Monitor
Activity Monitor is a built-in Mac tool that shows every program running on your computer right now. Open it by pressing Command+Space, typing "Activity Monitor", and pressing Enter. Click the "CPU" tab to see what is using your processor.
Look for programs you do not recognize or did not open yourself. Legitimate system processes have names like "kernel_task" or "WindowServer" and are normal. Suspicious names might include random strings of letters, misspellings of real apps (like "Chrom" instead of "Chrome"), or programs with no obvious purpose. If you see something unfamiliar, search for its name online before doing anything — many system processes sound strange but are harmless.
Do not force-quit programs unless you are sure they are malware; closing the wrong thing can crash your Mac. If you find something suspicious, note its name and search for removal instructions specific to that program.
Signs your Mac might have malware
Adware is the most common malware on macOS. You might see pop-up ads appearing even when you are not browsing, your browser homepage or search engine changed without your permission, or ads appearing in places they should not (like inside your email). These are annoying but removable.
Other signs include your Mac running much slower than usual, apps crashing frequently, or your Mac overheating even when you are not doing anything demanding. Malware can also cause your browser to redirect you to different websites than the ones you clicked, or show you fake security warnings telling you to download something.
Ransomware that locks your Mac and demands payment is extremely rare on macOS. If your screen is locked with a message demanding money, it is almost always a scareware scam — a fake warning, not actual malware. Force restart your Mac by holding the power button for 10 seconds, then restart normally.
Keeping your Mac protected going forward
Update macOS as soon as updates are available. Go to System Settings, click "General", then "Software Update" to check for updates. Apple releases security patches regularly, and staying current closes holes that malware exploits.
Be cautious about what you download and where you download it from. Malware on macOS usually arrives through infected files from untrusted websites, email attachments from people you do not know, or fake versions of popular programs. Stick to the App Store or official websites when downloading software.
Do not open email attachments from senders you do not recognize, and do not click links in unexpected emails even if they claim to be from your bank or Apple. Legitimate companies do not ask you to confirm passwords or payment information by email.
When to use a paid antivirus program
The free version of Malwarebytes is strong enough for most people. Paid antivirus programs like Norton, McAfee, or Kaspersky add real-time monitoring, which scans files as they arrive rather than waiting for you to run a manual scan. Real-time monitoring uses more of your Mac's processing power and battery, so it is a trade-off between protection and speed.
You do not need both Xprotect and a paid antivirus program running at the same time — they can conflict with each other. If you install a paid antivirus, it usually disables Xprotect automatically. Paid programs are worth considering if you download files frequently from sources you are not completely sure about, or if you share your Mac with other people who might be less careful about what they open.
Free antivirus programs for Mac are generally less reliable than paid ones or Malwarebytes. Avoid programs that claim to clean your Mac or speed it up — these are often adware themselves.
Removing malware you found
If Malwarebytes found something, click "Remove" in the scan results. Malwarebytes handles most common adware and malware automatically. After removal, restart your Mac to make sure the malware does not reload itself.
If you found something suspicious in Activity Monitor, search online for "[program name] removal" to find specific instructions. Some malware requires manual removal steps beyond just deleting the program. Do not guess — follow removal instructions from a trusted source like the program's official website or a security company you recognize.
After removing malware, check your browser settings. Go to Safari, Chrome, or Firefox settings and look at your homepage, search engine, and installed extensions. Adware often changes these. Reset them to what you want, and remove any browser extensions you do not recognize.
Frequently Asked Questions
Can Macs get viruses?
Yes, but differently than Windows PCs. Viruses that spread by copying themselves are rare on macOS. Adware and malware that steal information or show unwanted ads are common. Xprotect catches most of these automatically, but Malwarebytes finds additional threats.
Is Malwarebytes safe to download?
Yes. Malwarebytes is made by a legitimate security company and is widely used. Download it only from malwarebytes.com, not from other websites, to avoid getting a fake version.
Do I need antivirus if I only use the App Store?
App Store apps are scanned by Apple before they are published, so your risk is lower. Xprotect still runs in the background. If you download programs from websites or email, Malwarebytes adds an extra layer of protection.
What should I do if a website says my Mac has a virus?
Close that website immediately. These are fake warnings designed to scare you into downloading something. Your Mac does not know what website you are on, so it cannot tell you that you have a virus. Run Malwarebytes if you are worried, but the warning itself is not real.
How often should I scan my Mac?
If you are careful about what you download, scanning once a month with Malwarebytes is enough. If you download frequently or share your Mac with others, scan every two weeks. Xprotect runs automatically every day regardless.