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Microsoft Windows Defender Review

Microsoft Windows Defender has gone from strength to strength in recent years, but just how good is it really?


Windows Defender protected against all threats in tests by three separate organisations. It's free, already on Windows 10 and is very much the anti-malware suite to beat.


  • Excellent integrated Windows 10 interface
  • Excellent malware protection
  • No need to install third-party software
  • Free


  • Relatively high numbers of false positives in some tests
  • System impact isn't as low as you might expect

Key Specifications

  • Client for Windows
  • Built into Windows 8/8.1/10
  • Available for Windows Vista/7 as Microsoft Security Essentials
  • Parental controls
  • 5GB backup storage (OneDrive)

What is Microsoft Windows Defender?

Microsoft’s Windows Defender – the default virus protection built into Windows 7 and above – has gone from strength to strength in recent years, and its performance in recent tests by multiple independent firms has been conspicuously good.

It’s even being trialled for macOS under the name Microsoft Defender Advanced Threat Protection (ATP) for Mac, although the focus there is primarily to serve mixed-OS business environments.

Windows Defender impact on system performance isn’t too bad and is likely to be unnoticeable on reasonably well-specified PCs. However, using it in favour of third-party software may not provide the kind of performance boost you’d hope for.

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Windows Defender Antivirus

Microsoft Windows Defender is a default Antivirus for Windows 7 and above. It is completely free to install, no need to subscribe or pay a dime. Sounds like an absolute dream right?

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Microsoft Windows Defender – Features, set-up and usability

Windows Defender’s appearance and features vary depending on which version of the operating system you’re running it on. Windows 10’s Windows Defender Security Centre opens on a home screen with an overview of your protection status, including when Defender last updated itself and scanned for malware.

It also has dedicated tabs for different features. Virus and threat protection is home to your usual quick, full and custom scans, plus an intensive offline scan mode to tackle hard-to-remove threats. You can manually update virus definitions and enable or disable options such as cloud-based protection and real-time protection – this isn’t a good idea, though.

The device performance and health section monitors anything that might go wrong with your system over time and gives you a ‘Fresh start’ option that reinstalls Windows while keeping your files and most settings.

The firewall has its own tab where you can open ports, configure notifications and set different settings for private and public networks. App and browser control allows you to set the strictness of Microsoft’s SmartScreen utility, which can warn against or block apps that Microsoft’s remote verification service hasn’t seen before.

You can even disable notifications from Defender via the Virus & threat protection settings, giving it a very welcome silent detection mode.

Parental controls can be found under Family options. These provide device and account management for children who use Windows devices, allowing you to enable content filtering for the web, control the apps they install and the amount of time they spend in front of the screen. The latest update lets you impose fine-grained per-application time limits.

Other relatively recent additions are Defender’s integrated ransomware protection and file recovery features, which rely on Microsoft OneDrive as a secure cloud backup target. You only get 5GB of free space by default, but that might be enough for your most critical personal files.

You can even track your computers remotely if you use your Microsoft account to log in to your PC, while subscribing to Microsoft Intune adds remote wipe capabilities.

Related: Best Antivirus 2019

Microsoft Windows Defender – Performance

Testing facility AV-TEST AV Comparatives SE Labs
Real-World Threat Protection 100% 100% 100

Although Windows Defender was once an antivirus also-ran – something to keep you safe until you buy real internet security software – it’s improved immeasurably, to become the benchmark by which all other security software is measures. Its recent test results have been consistently excellent.

In AV-TEST’s latest results, it protected against all reference samples and all real-world malware exposure tests over a two month period, with just a single false positive misidentification of legitimate software. AV-Comparatives’ real-world tests confirmed the trend, giving Windows Defender an accuracy rate of 100%, although it eyebrow-raisingly classed 39 legitimate programs as potential malware.

In SE Labs’ most recent test, Windows Defender was one of just a handful of antivirus suites to get a perfect score, fully protecting against malicious programs with no misidentification of legitimate software.

Should I use Microsoft Windows Defender?

Microsoft’s integrated anti-malware tools are currently so effective that, unless you need specific features or a slight performance boost, there’s little point in installing third-party antivirus software unless you’re going for something with lots of useful extras or which provides a significant reduction in system resource use, such as Symantec’s Norton 360 Deluxe.


Free, effective, and already installed on your system, Windows Defender is hard to beat. Unless you want to secure multiple non-Windows devices in your home as well, or make use of specific features, there is little point in going large on an antivirus package when the free option is as good as this.

We continually check thousands of prices to show you the best deals. If you buy a product through our site we will earn a small commission from the retailer – a sort of automated referral fee – but our reviewers are always kept separate from this process. You can read more about how we make money in our Ethics Policy.

Best Paid Antivirus

Symantec Norton 360 Deluxe

Norton 360 Deluxe includes both antivirus and vpn software protection on up to 5 devices. Sign up for a year and save 62%.

Kaspersky Total Security

This multi-award winning cyber security product will protect you at all angles - from hackers, to malware and viruses. Sign up to Kaspersky Total Security for a year and save 30% off plus free installation.

Bitdefender Total Security 2020

Bitdefender Total Security 2020 - Rated 3rd top antivirus software on the market. Sign up now for a year and receive a near 60% off. This allows you to stay secure on the internet on up to 5 of your personal devices.

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