Start With the Signs
Before running anything, pay attention to what your Mac is actually doing. A sudden slowdown doesn’t automatically mean malware. Your storage could be nearly full. An old app could be misbehaving. Still, strange behavior that appears out of nowhere deserves a closer look.
• Your browser keeps changing its search page, even after you switch it back. Annoying, and definitely worth checking.
• The Mac runs hot while you’re doing almost nothing, with fans spinning loudly in the background.
• Random pop-ups appear outside the websites you’re visiting. That’s the one I’d take seriously.
Run a Malware Scan
macOS includes built-in security features that quietly block known threats, but I wouldn’t rely on that alone if you already suspect something is wrong. Run a scan with a trusted Mac security tool and let it inspect the system properly.
Keep the security software updated before scanning. Malware changes constantly, and an old threat database isn’t much use against newer junk.
Look Through Your Installed Apps
Open your Applications folder and slow down for a minute. Do you remember installing everything there? If something appeared recently and you don’t recognize it, investigate it before launching it.
Check Browser Extensions and Login Items
• A forgotten extension can be the culprit, especially if your search results suddenly look different.
• Login Items that you never approved shouldn’t get a free ride every time your Mac starts.
What If You Find Something Suspicious?
Don’t panic. Disconnecting from the internet is a sensible first move if you think malware is actively communicating with something outside your Mac. Then remove the suspicious software using a trusted security tool or its proper uninstaller.
Change important passwords from a different, trusted device if you believe the malware may have captured them. And update macOS afterward.