Does Your Mac Have Malware? Common Signs

  • Browser redirecting to unexpected search engines or showing more ads than usual
  • New browser extensions you did not install
  • Mac running noticeably slower or fan running constantly
  • Pop-ups claiming your Mac is infected (often fake — these are themselves malware)
  • Applications opening that you did not launch
  • Unfamiliar apps appearing in your Applications folder

Step 1: Run Malwarebytes for Mac (Free)

  1. 1

    Download from malwarebytes.com

    Go to malwarebytes.com and download Malwarebytes for Mac. The free version detects and removes malware — you do not need the paid Premium subscription for a one-off scan. Install and open it.

  2. 2

    Run a scan

    Click Scan. Malwarebytes scans your Mac for known malware, adware, potentially unwanted programs (PUPs) and browser hijackers. The scan typically takes 1–3 minutes. If threats are found, click Quarantine to remove them.

Step 2: Check Login Items and Launch Agents

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    System Settings → General → Login Items

    Review the list of apps that launch at startup. Remove anything you do not recognise by selecting it and clicking the minus button. Malware often installs itself as a Login Item to ensure it runs every time you start your Mac.

  2. 4

    Check Launch Agents (advanced)

    Open Finder → Go → Go to Folder → type ~/Library/LaunchAgents. Review the files. Legitimate system files have Apple or known software names. Files with random strings of letters or unfamiliar names may be malware. Do not delete files you are not sure about — research the name first or let Malwarebytes handle removal.

Step 3: Check Browser Extensions

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    Review and remove suspicious extensions

    Safari: Safari menu → Settings → Extensions. Remove anything you did not intentionally install. Chrome: three dots → Extensions → Manage Extensions. Remove any unfamiliar extensions. Browser extensions are the most common way adware and browser hijackers operate on Macs.

Step 4: Check Activity Monitor

Open Activity Monitor (Applications → Utilities → Activity Monitor). Sort by CPU usage. Look for processes using high CPU that you do not recognise. Google any unfamiliar process names to determine if they are legitimate. Malware often runs as background processes consuming CPU.

Mac’s built-in protectionsmacOS includes XProtect (signature-based malware scanner that runs automatically), Gatekeeper (prevents running apps from unknown developers without explicit permission), and Notarization (Apple scans apps submitted to the App Store). These provide solid baseline protection. Malwarebytes catches threats that slip past these defences, particularly adware and PUPs.

Frequently Asked Questions

Yes — Mac malware is less common than Windows malware but absolutely exists and is increasing. The most common Mac threats are adware (injecting ads into browsers), browser hijackers (changing default search engine), and fake security software (pop-ups claiming your Mac is infected, asking you to install a “cleaner” — the cleaner is the malware). Macs are no longer the safe havens they were once considered to be as their market share has grown.
CleanMyMac X has a malware removal module that is reasonably effective. However, it is a paid app primarily marketed as a system cleaner. For malware scanning specifically, Malwarebytes for Mac (free) is as effective or better for malware detection and removal. CleanMyMac’s disk cleaning features are separate from its malware scanning — do not confuse cleaning up disk space with removing malware.