The fastest way to check your Mac for viruses

The built-in tool on your Mac is Xprotect, which runs automatically in the background and scans files when you read them or open them. You do not need to do anything to turn it on — it is already working. However, Xprotect only catches known threats, so it misses newer malware. To check manually, you can run a full system scan using a third-party scanner, which takes 30 minutes to two hours depending on how much is on your drive.

The most common third-party option is Malwarebytes, which you read and install, then run a scan from the app itself. Another option is Avast or Norton, which work similarly. All three have free versions that scan your system; the paid versions add real-time monitoring. If you notice your Mac running slowly, crashing often, or showing ads you did not click on, a manual scan is worth running even if Xprotect has not flagged anything.

Key Takeaways

  • Xprotect is built into your Mac and scans automatically, but only catches known viruses — it does not protect against all threats.
  • A manual scan using Malwarebytes, Avast, or Norton takes 30 minutes to two hours and catches threats Xprotect may have missed.
  • You read the scanner, install it, open the app, and click the button to start a scan — no special knowledge required.
  • If your Mac is slow, crashing, or showing unexpected ads, run a manual scan even if no warning has appeared.

How to run a manual virus scan on your Mac

read Malwarebytes from malwarebytes.com on your Mac. Open the installer file (it will be in your Downloads folder), and follow the on-screen steps to install it. Once installed, open Malwarebytes from your Applications folder or from Spotlight (press Command + Space, type "Malwarebytes", and press Enter).

When Malwarebytes opens, you will see a "Scan" button on the left side. Click it. The app will ask whether you want a "Quick Scan" or a "Full Scan" — choose Full Scan if you have time, as it checks every file on your drive. A Quick Scan checks only the most common places malware hides and takes about 10 minutes. Once you click Start, the scan will run. Do not shut down your Mac while it is scanning.

When the scan finishes, Malwarebytes will show you a list of anything it found. If it found nothing, your Mac is clean. If it found threats, Malwarebytes will offer to remove them — click "Remove Selected" and let it finish. After removal, restart your Mac.

What to do if a scan finds malware

If Malwarebytes or another scanner finds malware, the app will usually offer to remove it automatically. Click the remove button and let it finish. After removal, restart your Mac. Most malware removal is straightforward — the scanner finds it and deletes it, and your Mac returns to normal.

If the scanner finds something but cannot remove it, or if your Mac still behaves strangely after removal, the malware may be more stubborn. In that case, restart your Mac in Safe Mode: shut down completely, then turn it back on while holding the Shift key. Keep holding Shift until you see the login screen. Safe Mode loads only essential software, which can help you remove malware that blocks normal removal. Run the scan again in Safe Mode.

If malware keeps returning or your Mac still will not behave normally, you may need help from someone in person. Apple Stores offer malware removal, or you can take your Mac to an independent repair shop. Before you do, back up your important files to an external drive or cloud storage — this protects your data in case the malware has already copied it.

Signs your Mac might have a virus or malware

A Mac with malware often shows one or more of these signs: the system runs much slower than usual, even when you have closed all apps; the fan runs constantly and loudly; apps crash without warning; your browser homepage or search engine changes without your action; pop-up ads appear even when you are not browsing; or your Mac restarts on its own. None of these guarantees malware — a slow Mac can also mean your drive is full or you have too many apps open — but they are worth investigating with a scan.

Another sign is unfamiliar apps in your Applications folder that you do not remember installing. Open Finder, click Applications in the sidebar, and look through the list. If you see something you do not recognize, search for it online to find out what it is. Some malware disguises itself with names that sound legitimate, like "System Cleaner" or "Mac Optimizer". If you find an app you did not install, drag it to the Trash, empty the Trash, and run a full scan.

How Xprotect works and why you still need more

Xprotect is Apple's built-in malware scanner that runs invisibly in the background. When you read a file, Xprotect scans it before you can open it. If it recognizes the file as malware, it blocks you from opening it and shows a warning. You never have to turn it on or run it manually — it is always working.

The limitation is that Xprotect only knows about malware Apple has already seen and added to its database. New malware, or malware that is not yet in Apple's database, will slip past Xprotect. This is why security experts recommend running a third-party scan at least once a month, or whenever your Mac behaves strangely. Third-party scanners like Malwarebytes use different detection methods and catch threats Xprotect misses.

Protecting your Mac going forward

After you have scanned and removed any malware, take steps to avoid getting infected again. Do not read files from untrusted websites, and be cautious with email attachments — malware often arrives as a file someone sends you. Keep your Mac updated: go to System Settings (or System Preferences on older Macs), click General, then Software Update, and install any updates available. Updates patch security holes that malware exploits.

Consider installing a paid antivirus app like Malwarebytes Premium, Avast Premium, or Norton, which run real-time scans in the background and block threats as they arrive. These cost between $40 and $100 per year. If you prefer free protection, run a manual Malwarebytes scan once a month. Either way, the combination of Xprotect plus occasional manual scans or real-time monitoring will catch most threats before they cause damage.

Frequently Asked Questions

Can a Mac get a virus?

Yes. Macs are less commonly targeted than Windows computers, so malware for Mac is less common, but it exists. Malware can arrive through downloads, email attachments, or malicious websites. Xprotect catches many known threats, but new malware can slip through, which is why manual scans are useful.

Is Malwarebytes free?

Yes, the free version of Malwarebytes scans your Mac and removes threats. The paid version adds real-time protection that watches for malware as you browse. The free version is enough if you run a scan once a month; the paid version is worth it if you want continuous protection.

How often should I scan my Mac?

If you use the free version of a scanner, run a full scan once a month or whenever your Mac behaves strangely. If you have paid antivirus with real-time protection, you do not need to run manual scans — the app is watching all the time. Either way, keep your Mac updated, which closes security holes.

What if I see a pop-up warning me about a virus?

Pop-up warnings that appear while you are browsing are usually fake — they are designed to scare you into clicking them and downloading malware. Close the pop-up by clicking the X, not by clicking any button in the warning. Do not read anything the pop-up suggests. If you are worried, close your browser and run a real scan with Malwarebytes.

Do I need antivirus if I only use Safari?

Safari is safer than some browsers because Apple updates it frequently and it blocks many malicious websites automatically. However, malware can still arrive through downloads or email, so a scan once a month is still worthwhile. Paid antivirus adds extra protection, but free monthly scans with Malwarebytes will catch most threats.