Free security software for Windows 11 and Windows 10

WindowsUpdated

Windows 11 and Windows 10 come with free security software already installed. It's called Windows Security, and Microsoft says it's built into Windows, so your device is protected from the moment you start it up. It includes Microsoft Defender Antivirus, a firewall and protection against harmful apps and downloads.

Quick answer

The Windows Security app is built into Windows and includes Microsoft Defender Antivirus, Windows Firewall, reputation-based protection and, on new Windows 11 installs, Smart App Control. Check that real-time protection and the firewall are on. Treat pop-ups offering a free virus scan as scams, and download software only from the Microsoft Store or official Microsoft partner websites.

What free security software comes with Windows?

The Windows Security app. Microsoft calls it a comprehensive security solution integrated into Windows. The UK's National Cyber Security Centre (NCSC) says antivirus is often included for free in the operating systems that run Windows and Apple computers, and that making sure it's switched on makes you instantly safer.

Inside the app:

  • Virus & threat protection: Microsoft Defender Antivirus, which Microsoft says continuously scans your device for potential threats. Windows downloads its latest security intelligence automatically through Windows Update.
  • Firewall & network protection: Microsoft says Windows Firewall helps protect your device by filtering network traffic and blocking unauthorised access.
  • App & browser control: reputation-based protection, which uses Microsoft Defender SmartScreen to check the reputation of apps and files you download, and Smart App Control.
  • Device encryption: in Settings rather than the app. Microsoft says Device Encryption turns on BitLocker automatically when you first sign in with a Microsoft account, and works on Windows Home devices too.

How do I check Windows Security is switched on?

Open the Windows Security app by searching the Start menu for Windows Security, then work through these.

  1. Real-time protection: select Virus & threat protection > Manage settings and check Real-time protection is on. Microsoft says that if you switch it off, it turns back on automatically after a short while.
  2. Updates: select Virus & threat protection > Protection updates > Check for updates.
  3. Firewall: select Firewall & network protection, choose your network profile (Domain, Private or Public), and switch Microsoft Defender Firewall to On.
  4. Downloads: select App & browser control > Reputation-based protection and turn on "Check apps and files". Microsoft says potentially unwanted app blocking is turned off by default for consumers and recommends turning it on, blocking both apps and downloads.
  5. Encryption: open Settings > Privacy & security > Device encryption and switch it on. If you use a local account, Microsoft says it isn't turned on automatically.

To run a scan, select Virus & threat protection, then Quick scan, or Scan options for a Full scan.

What is Smart App Control?

A Windows 11 feature that Microsoft says adds significant protection from new and emerging threats by blocking apps that are malicious or untrusted. It also blocks potentially unwanted apps.

It starts in evaluation mode, where Windows checks whether your device is a good candidate and blocks nothing. After that it's either on or off. Microsoft says Smart App Control can be used on new Windows 11 installs only, and isn't available in Windows 10. Check yours in Windows Security > App & browser control > Smart App Control settings.

Is Windows 10 still protected for free?

Windows 10 support ended on 14 October 2025. Microsoft says a Windows 10 computer no longer receives security updates after that date, though it continues to work. The NCSC's device guidance also says older versions of Windows will benefit from third-party antivirus.

Two of the options Microsoft lists:

  1. Upgrade to Windows 11. Microsoft says the upgrade is free for Windows 10 PCs running version 22H2 that meet the minimum hardware requirements. To check eligibility, go to Start > Settings > Update & Security > Windows Update and select Check for updates.
  2. Extended Security Updates (ESU). Microsoft's consumer programme covers a Windows 10 device until 12 October 2027, for people who need more time before moving.

Should I install a free antivirus as well?

You don't need two. Microsoft says that if you install a compatible non-Microsoft antivirus program, Microsoft Defender Antivirus automatically turns itself off, and a setting appears for limited periodic scanning. The NCSC doesn't recommend more than one antivirus product on any device, because the benefit is minimal and the products may conflict.

The NCSC also says new computers often come with a trial version of a separate antivirus product installed, and when the trial expires you'll have to pay or register to keep using it. If you want a different product, the US Cybersecurity and Infrastructure Security Agency (CISA) says the choice may come down to recommendations, features, availability or price, and to turn on automatic definition updates where offered.

How do I spot a fake free antivirus offer?

Look at how it reached you. Microsoft says its error and warning messages never include a phone number, and that it doesn't send unsolicited emails or make unsolicited phone calls. The US Federal Trade Commission (FTC) says scammers create fake security warnings that tell you to call a number for tech support, ask for remote access, claim to find a malicious program and offer to remove it for a fee.

Where to download safely:

  • Microsoft says to download software only from official Microsoft partner websites or the Microsoft Store.
  • The FTC says don't click on ads to download software. Type the website's address in yourself.
  • The FTC also says don't use unfamiliar websites to download free stuff such as music, films or games.

If you've already been caught out, Microsoft says to call your card provider to contest the charges, and to consider resetting the device if you gave scammers access. The FTC says to change any password you shared, and anywhere else you used it. Report it to Microsoft at microsoft.com/reportascam.

Where Failshot fits

Your password is the first layer. Failshot is the second: second layer device security, for the moment someone sits down at your computer and unlocks it.

Failshot for Windows is coming soon. Failshot for Mac is out now, for macOS 14 or later:

  • While it's on, it photographs whoever unlocks your Mac, then, with Pro, records a 5-second video.
  • With the Mac's built-in camera, the green light comes on, and its window tells whoever unlocked the Mac that the unlock was photographed.
  • With Pro, turn on alerts and Failshot emails you about an unlock you don't confirm as yours, a wrong Failshot PIN or answer, or its camera access being switched off while it's on.
  • Switching it off, or quitting it from its menu, takes Touch ID or your Failshot PIN and answer, never your Mac password.

Get it from failshot.app. Free to download. It's free to use. Pro adds video, email alerts and the encrypted vault, and you can try Pro free for 7 days. Your card is taken at sign-up and charged on day 8 unless you cancel. iPhone and Android versions are coming soon too.

More questions

Is Windows Security really free?

It's built into Windows. Microsoft says the app is built in, so your device is protected from the moment you start it up. The NCSC says antivirus is often included for free in the operating systems that run Windows computers.

Is Microsoft Defender the same as Windows Security?

Microsoft Defender Antivirus is one part of the Windows Security app. The app also includes Windows Firewall, App & browser control with SmartScreen, and Smart App Control on new Windows 11 installs.

Why has Microsoft Defender turned itself off?

One reason is another antivirus. Microsoft says Defender automatically disables itself when you install a compatible non-Microsoft antivirus program, and the Windows Security app shows it as turned off. A setting then appears for limited periodic scanning.

Will a real Microsoft warning ask me to call a number?

No. Microsoft says its error and warning messages never include a phone number, and it doesn't make unsolicited phone calls. Close the page and report it at microsoft.com/reportascam.

Can I still get free security updates for Windows 10?

Microsoft says Windows 10 no longer receives security updates after 14 October 2025. Eligible PCs can upgrade to Windows 11 free, and the consumer Extended Security Updates programme covers Windows 10 devices until 12 October 2027.

Sources