How to Know If Your System Is Infected

Your Mac’s behavior offers clues that it’s been infected. For example, the machine runs slower than usual, its fans run constantly, it stops responding, or it suddenly reboots. If you find browser extensions, toolbars, or plug-ins you didn’t install, notice third-party applications you never asked for, or your browser’s settings have mysteriously changed, malware is probably the culprit. An adware infection reveals itself with unexpected ads and pop-ups on your desktop, browser home page, or other websites you visit.

Types of Infections

A variety of bugs and malicious software can infect your Mac, but the removal process is generally the same. Understanding the terms can be helpful.

Malware

Malware, short for malicious software, is any software that intentionally harms a computer or performs user-hostile actions. It’s a catch-all term that includes:

Adware, which displays unwanted ads. Spyware, which tracks your behavior. Ransomware, which encrypts your user files and demands payment to decrypt them. Trojans, which seem innocent on the surface but contain hidden trouble.

Potentially Unwanted Software (PUPs)

A potentially unwanted program might perform some valuable function, but it comes bundled with unwanted side effects. A PUP might change your home page and search engine, add malware to your computer, or steal your credit card information when you pay for the application’s dubious “service.” Often, people install PUPs because they were tricked by dishonest ads or clicked through installer steps without reading them. PUPs are the most common type of malware found on Macs.

Viruses

A virus spreads from computer to computer like a disease, attaching to other files to infect more and more devices. Viruses use the internet, local network connections, or USB drives to propagate. There are a few steps to take to clean up your system and remove unwanted malware for good.

Kill Running Processes

The first step in tracking down and eliminating a bad actor in your system is closing apps and processes. Here’s how:

Find and Uninstall the Malicious Program

Next, it’s time to find and uninstall the unwanted program. Even if you didn’t see any malware in the Activity Monitor, still go through this process.

Remove Login Items

Login items are programs that launch automatically when your computer boots. If you see an application’s window as soon as you log in to your Mac, that’s a login item. Malware often sets itself up as a login item so it can relaunch every time your computer boots. Here’s how to find and delete them:

Clean Your Browsers

Many forms of adware and malware install some sort of browser extension or change your browser settings in some way. Most commonly, they change your home page, search engine, or new tab page. Here’s how to make sure your browsers are clean.

Run a Malware Scan

To make sure you’ve removed every piece of malicious software, run a trusted malware scanner such as Malwarebytes. Malwarebytes scans your system for known malware. If any dangerous files are found, they’re transferred to the Quarantine section, where they can be successfully deleted.

Extra: Tips for Staying Malware-Free

Although macOS comes with some built-in security features, changing your browsing habits is an important component of staying malware-free. Here are a few tips:

Avoid untrustworthy downloads, especially torrents from sites such as BitTorrent. Always be aware of what you’re installing. Read every word in an installer to avoid inadvertently agreeing to install unwanted software. Keep your software up to date. In particular, always download the new versions of macOS, especially the security updates.