How to check if my Mac has a virus or malware?

If your Mac shows signs of malware, such as sudden slowdowns, unfamiliar apps, pop-up ads, browser redirects, or rapid battery drain, check and clean your system using these steps: first, open Activity Monitor to spot and quit suspicious processes; second, run a scan with trusted antivirus apps like Malwarebytes or ClamXAV; third, check login items in System Settings and uninstall unfamiliar apps; fourth, reset browser settings in Safari or Chrome if affected by adware; finally, keep your system updated and avoid risky downloads to prevent future issues.

如果你're worried your Mac might have a virus or malware, you’re not alone. While macOS has strong built-in security features, it’s still possible for malicious software to slip through—especially if you’ve downloaded something from an untrusted source or clicked a suspicious link. The good news is there are clear signs and steps you can take to check and clean your system.

Check for unusual activity or performance issues

Malware often causes noticeable changes in how your Mac behaves. Here are some red flags to watch for:

• Your Mac suddenly runs slower than usual
• You see unfamiliar apps or browser extensions appearing out of nowhere
• Pop-up ads keep showing up even when you’re not browsing
• Your web browser redirects to strange websites
• Battery drains faster than normal

If you notice multiple symptoms like these, it's worth investigating further.

Use Activity Monitor to spot suspicious processes

Activity Monitor is a built-in tool that shows what’s running on your Mac. Here’s how to use it to look for malware:

1. Open Applications > Utilities > Activity Monitor
2. Look through the list of running processes
3. Pay attention to any unfamiliar names using high CPU or network resources

Some malware disguises itself with names similar to legitimate system processes (like “kernel_task” or “mds” — but fake versions exist). If you see something suspicious:

• Google the process name to verify
• If it looks dodgy, select it and click the X button to quit

Keep in mind: quitting the wrong process could cause instability, so only close things you’re sure about.

Run a scan with a trusted antivirus app

Although macOS doesn’t come with antivirus software pre-installed, there are reliable free tools you can use:

• Malwarebytes for Mac – scans for adware, spyware, and other threats
• ClamXAV – open-source antivirus scanner

Here’s how to use them:

• Download and install one of these tools
• Run a full system scan
• Follow the prompts to remove any infected files

These apps aren’t replacements for Apple’s built-in protections, but they offer an extra layer of defense, especially if you're unsure what’s going on.

Check login items and uninstall suspicious apps

Malware sometimes sets itself to launch automatically when you log in. To check:

1. Go to System Settings > Users & Groups > Login Items
2. Review the list and remove anything unfamiliar

Also, go through your Applications folder and delete any apps you don’t remember installing. Right-click and choose Move to Trash, then empty it just to be safe.

Reset your browser settings if needed

If pop-ups or redirects are mainly happening in Safari or Chrome, your browser might be compromised by adware or extensions.

For Safari:

• Go to Preferences > Extensions and disable unknown add-ons
• Reset Safari: Safari > Safari > Reset Safari

For Chrome:

• Go to Settings > Extensions and remove anything suspicious
• Use the Reset settings option under Advanced > Reset and clean up

Most of the time, a slow or odd-performing Mac isn’t due to malware—it could just be a bloated cache or too many background apps. But if you've been clicking around sketchy sites or downloading pirated software, it's worth checking thoroughly. Keep your OS and apps updated, avoid opening attachments from unknown senders, and you’ll stay mostly protected.

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