Thanks to Microsoft Defender and additional security features in Windows 11, Microsoft says the average user doesn’t need to install antivirus software. Is that good advice?
For years, Microsoft has shipped built-in antivirus software with Windows. Microsoft Defender is built into the operating system by default, whether you have a Home, Pro, or Enterprise license. This might make you wonder if Microsoft Defender provides enough protection.
According to Microsoft, the answer is simple: yes. In a blog post, Microsoft writes that ‘Defender provides protection against everyday risks without the need for additional software’. The ‘average’ user therefore doesn’t need to look for third-party software, because Windows 11 is ‘the most secure version yet’. Microsoft is obviously biased, but is the boasting justified?
What does an antivirus do?
You can think of antivirus software like Microsoft Defender as a security alarm. It continuously scans files and (new) applications for potential viruses that could infect your device. Most antivirus software doesn’t just alert you to viruses, but also removes them preventatively. If that’s not the case, you need to find a new solution urgently.
The advantage of Microsoft Defender is that it’s available for free and runs by default on every Windows PC, both Windows 11 and Windows 10. The software has made great strides in recent years. Anyone who relied on Defender to keep their PC safe during the days of Windows XP or Windows 8.1 had a lot of faith in the goodness of humanity.
Microsoft wouldn’t be Microsoft if it didn’t cause confusion with different versions of Defender. For instance, there is the Defender app, also available for mobile and Mac, which requires a 365 subscription. However, the standard features of Defender are available in Windows without a subscription.
Is Defender a good antivirus?
The short answer: yes, Microsoft Defender is a more than capable antivirus. For this, we rely on independent comparison tests from AV-Test, which regularly examines antivirus software for home and business users. The tests evaluate each solution on three aspects: protection, performance, and usability.
In the most recent test (February 2026), both the consumer version (Defender Antivirus Consumer 4.18) and the professional version (Defender Antivirus Enterprise 4.18) received a perfect score. Solutions from specialized parties like Norton, Withsecure, and Sophos do not score any better. The Enterprise version of Defender is not free and costs three euros per month for a standalone subscription.
Microsoft Defender receives a perfect score in independent tests.
However, antivirus vendors have excellent sales and marketing departments. As a result, antivirus programs like McAfee continue to appear as bloatware on commercial PCs, including professional devices, without offering any effective added value. They try to push you toward a subscription you don’t need with sneaky and loud notifications claiming your PC is infected. A decent antivirus isn’t loud; it does its job in the background.
Windows Security
Defender doesn’t operate in a vacuum. Windows has several security settings you can enable. SmartScreen is a feature that warns you before you click on a suspicious website or file link, while Smart App Control blocks malicious applications. Windows also has built-in protection against ransomware, which we review in this guide.
The built-in security only works if you set everything up correctly. You do this via the Windows Security app. Microsoft recommends the following settings:
- Virus threat protection: enable real-time and cloud-delivered protection. This ensures Defender blocks malware before it runs and gives Defender access to security data in the cloud. Microsoft does ask to send sample files to the cloud for this.
- App browser control: turn on both Smart App Control and Reputation-based protection (SmartScreen). This protects your device from malicious apps, files, and websites.
- Ransomware protection: automatically backs up your local files to OneDrive.
While backups are your life insurance against ransomware, Microsoft’s last tip feels mostly like a way to push OneDrive onto Windows users. Know that other, equivalent options exist for duplicating files, both physically and in the cloud. The 3-2-1 rule remains the recommended advice.
Enough for many
The combination of Defender with other Windows settings provides you with solid basic security. Microsoft can therefore rightly claim that Defender will suffice as an antivirus for many users. An individual Windows user does not need to take out a paid subscription for third-party software. The conclusion of our previous analysis remains unchanged.
Installing multiple antivirus programs on your PC can even have negative consequences. An antivirus runs continuously in the background—you might as well not have one if you’re going to turn it off—and therefore consumes memory. The more programs you run simultaneously, the more it affects your PC’s performance.
But not for everyone
Still, Microsoft admits that Defender has its limits. Users managing multiple devices or sharing their device will need additional security. The situation is also different in a business context, as security needs are higher. Professional software, whether from Microsoft or another security specialist, covers those needs better than the free version of Defender.
Furthermore, you must not forget that an antivirus is only one piece of the security puzzle. An antivirus is like an alarm that only goes off when burglars are at your front door. If you want to avoid that, you need to invest in a good fence. Think of a firewall and tools that monitor the network, combined with MFA and zero trust to compensate for the danger of stolen or weak passwords. All these different elements do not offer complete protection on their own, but it is the combination that makes your digital environment secure.
The most important things remain the basic principles. You can have the best security solutions, but if you don’t keep your software up to date and poorly secure accounts and access, hackers will break in without effort. Security still starts with installing a good lock and not leaving your key in the door.
An antivirus is like an alarm that only goes off when burglars are at your front door. If you want to avoid that, you need to invest in a good fence.