Antivirus

Software that monitors files, processes, and network activity in real time to detect and block known malware signatures plus suspicious behavior patterns.

Why it matters

On a modern Windows 11 machine, Microsoft Defender catches 99.7 percent of in-the-wild malware (AV-TEST 2025). Paid antivirus catches 99.9 to 100 percent. The marginal protection is real but small for a casual home user. The real reasons to pay are the bundled extras: phishing-blocking DNS, ransomware rollback, password manager, and family controls.

For a power user with sensitive accounts (financial, medical, business) the paid tier earns its keep. For a kid's homework laptop, Defender is enough.

Best practices

Run only one antivirus at a time; two engines fight each other and slow the machine. Test your AV's protection at amtso.org's safe test files before trusting it. Update signatures daily (most AVs auto-update).

The most common malware vector in 2026 is not a virus download but a fake support pop-up that talks you into installing the malware yourself. No antivirus blocks social engineering reliably; situational awareness does.

Frequently asked

Is Microsoft Defender enough?

For a casual home user on Windows 11 with safe browsing habits, yes. For someone managing multiple sensitive accounts, working from home with sensitive data, or sharing the device with a kid who clicks everything, paid antivirus adds enough phishing and ransomware protection to be worth the $30 to $80 per year.