Is Windows Defender good enough, or do you need third-party antivirus software?

In previous iterations of Windows, it was well worth having a third-party antivirus package installed, but times change. Microsoft has continued to improve its virus-busting software over the years.

In fact, more than 50% of Windows 10 users rely on it. But although it is now widely accepted that Windows Security has improved, it doesn’t rate as highly as some third-party packages in our own independent antivirus tests.

Here, our Which? Tech Support experts take a closer look at the pre-installed security features on Windows. Plus, we review some of the most popular free antivirus packages to see if you should swap.

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Question of the month: is Windows Security good enough?

‘I’ve just read the April 2022 issue of Which? Computing and I’m staggered that you didn’t recommend Microsoft Defender as a free security software for Windows 10 and 11. Why not?

'When you have your main account set as a local account (with an admin account never used), then this is the way to go. I’ve done this on my Windows 10 and now 11 account for years and have never had any issues. In a local account, there just isn’t anything for viruses to latch onto.’

Which? Computing member

Our expert says:

'One of Windows Defender's biggest pros is that it runs automatically "out of the box" – there's no setup required. We've heard from some Which? Computing members who struggle with installing software correctly, so this negates that concern. Defender is also lightweight and offers auto-updates.

'Unlike a lot of free, third-party antivirus packages, you never get ads or pop-ups on Defender requesting payment for extra protection. This can be a real pain for some Which? Computing members.

'In the original article, we made it clear that Defender offers a reasonable level of defence, but based on our lab tests it won’t provide additional protection against phishing attacks unless you also use Microsoft Edge as your browser. It doesn’t always block potentially dangerous files from downloading – although it does step in if you end up running it – and also scores poorly on false positives.

'Overall, it’s pretty effective. But you can do better without having to pay a penny by using our recommended best free antivirus software.'

Which? Tech Support

What is Windows Security and what does it offer?

Windows Security is a pre-installed antivirus app built into Windows 10 and Windows 11 computers. Microsoft says that if you have another antivirus app installed and turned on, Microsoft Defender will turn off automatically.

Click the Windows logo in the bottom left of your screen (or centre, if you're using Windows 11), type Windows Security and you'll find yourself on the Home dashboard. This splits the app's key features into sections, as shown below:

From the Virus & threat protection menu, you can run a quick scan, or click Scan options to run a full scan, which obviously takes longer. In the same window, you'll see a list of 'allowed threats' and a history of the latest protection actions taken by Windows Security.

The App & browser control tab (on the far left) will tell you if there are any apps on your computer that could be stealing personal data.

If you're using a computer shared between family members, the Family options tab (on the far left) lets you control user access. For example, you can create a child's account that restricts access to certain websites, or set 'good screen time habits' and limit the amount of time others can use the computer.

By default, Windows Security will notify you automatically if it detects threats, or if any files or activities are blocked.

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Which? expert reviews uncover the best antivirus software

Third-party antivirus programs provide extra levels of security that Windows does not offer, such as network scanners, banking browsers and dark web monitoring.

If you do decide to use another antivirus package, then you can save from £45 to £118 a year by choosing a good free program. We’ve tested a selection of popular free antivirus packages (including those listed below), but you'll have to consult our full reviews (see best free antivirus software) to find out which we recommend.

Avast Free Antivirus

Avast is undoubtedly one of the best-known antivirus companies. Its free package is compatible with PC and Mac and includes wi-fi network security, which is designed to prevent hackers from piggybacking onto your network.

There's also a Safe Browsing feature that blocks malicious websites and suspicious downloads.

AVG Antivirus Free

AVG's free-to-download tool runs on Windows and Mac. It has multiple layers of security that include malware protection and an email shield, which blocks dangerous attachments and phishing links.

Real-time updates work hand in hand with what the brand refers to as 'the world's largest virus database'.

Avira Antivirus Free

Avira's software is split into three key categories: security, privacy and performance. Starting with security, you can run a full virus scan or use the quarantine tool to repair or delete unsafe files. There's also a software updater that checks your installed apps and a firewall aiming to block hackers.

Avira's browser tool will also attempt to block ads on Google Chrome and Firefox. Meanwhile, the list of performance-based features includes a cleaner (to free up space on your computer) and an optimiser tool that's meant to 'start your device faster'.

To see which free and paid-for antivirus packages come highly recommended courtesy of our expert lab tests, see our pick of the best antivirus software.

Join Which? Tech Support

Which? Tech Support can help you keep you on top of your home tech. Our experts explain things clearly so that you can resolve issues and feel more confident using your devices.

Get unlimited 1-2-1 expert support:

• By phone – clear guidance in choosing, setting up, using and resolving issues with your home tech devices.
• By email – outline the issue and we’ll email you our answer.
• By remote fix – we connect securely from our office to your home computer and resolve issues while you watch.
• In print – Which? Computing magazine, six issues a year delivered to your door.

You can join Which? Tech Support for £4.99 a month. You can cancel at any time.

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