Windows free Antivirus: is Defender enough?

The free antivirus built into Windows, Microsoft Defender, might not be enough to fight all threats. In general, it can be said that this antivirus is a good solution to protect your PC or laptop, especially if you use it primarily for home purposes; to assess its effectiveness, however, we tested it against four common threats, comparing it with other paid antivirus software such as McAfee and Bitdefender.

Free antivirus: how much protection does Microsoft Defender offer?

Before moving on to the results of our test, let's look at the Microsoft Defender features. Windows' free antivirus handles file and application checks through real-time protection, with constant updates that allow it to recognise the latest threats.

Microsoft Defender SmartScreen works alongside the antivirus, protecting users from phishing and sites containing malware, as well as potentially harmful downloads and applications. Comprehensive protection that cannot be missing on modern operating systems.

For ransomware, Defender has some specific features such as "controlled folder access" which prevents untrusted applications from modifying files in protected folders.

These protection tools are freely accessible through the Windows operating system and do not require an additional licence: a real convenience. Bearing this in mind, let's now see how Defender performs in our tests.

Test 1: phishing e-mail

Our first test was carried out with a classic phishing attempt. You receive an e-mail that appears to be sent from PayPal, with the message using the logo, colours and graphics of the original service.

In the message, the user is invited to click on the link to resolve an issue with their account.

The domain looks like PayPal's, but there are some small differences. Once you click the link, you are directed to a fake page created to steal the user's credentials.

In this case, the free version of Defender integrated into Windows operating systems does not perform a preventive check of the links in the e-mail. To use this feature you need to subscribe to the Microsoft 365 service.

Once you click on the link, however, Microsoft Defender SmartScreen can intervene, the feature built into Windows and Microsoft Edge that checks the websites you visit and can block those recognised as dangerous or used for phishing.

By contrast, the McAfee antivirus blocked the link in less than a second, showing us information about the source of the link. Not only does this eliminate the risks, but it also lets you understand why that link was judged dangerous. Unlike Defender, McAfee has specific tools for protection during browsing.

WebAdvisor can block phishing and malware sites if you click on potentially harmful links, checking downloads from suspicious sites for possible risks.

Test 2: attachment containing ransomware

The second test concerns a more dangerous threat, namely ransomware. This is malware designed to encrypt files on your device, then ask the victim for a ransom payment to recover their data.

It is a tactic commonly used by hackers to blackmail companies and individuals by encrypting important files or user data. Typically, ransomware is hidden in an e-mail attachment.

Again, Microsoft Defender Antivirus does not perform a preventive check of the attachment while it is in the mailbox. Once the file is downloaded to your PC, however, Defender's real-time protection comes into play, which can analyse it and detect any threats.

In this case, McAfee antivirus intervened in real time, blocking the ransomware immediately.

Microsoft Defender does have the aforementioned feature called Controlled Folder Access, useful for increasing protection against ransomware attacks. When activated on folders to be protected, this feature prevents untrusted applications from modifying files.

In general, since ransomware attacks are very dangerous it is advisable to regularly back up important files, so you have a copy of your data in case of ransomware or other problems.

Test 3: fake banking website

In the third test carried out, a very common phishing technique was reproduced: a link leads to a page identical to that of an Italian bank with logo, colours and login screen that appear authentic but the catch is in the address, which has a small difference from the original domain.

The aim of the scam is to get the user to enter username, password or other sensitive financial information through a website very similar to the real one.

Antivirus programmes should block the page before access but in the test Microsoft Defender did not immediately block the page or show warnings, allowing us to interact with the site. The block occurred after seconds or minutes of staying on the page.

By contrast McAfee immediately blocked the page, showing us a phishing warning. Against this type of threat, Windows antivirus uses Microsoft Defender SmartScreen, a feature able to analyse visited pages and then compare addresses with a dynamic list of phishing and malware sites reported.

In the case of McAfee, the WebAdvisor uses tools dedicated to protecting browsing and can block phishing sites when a link considered dangerous is opened.

Test 4: USB stick with an infected file

The last test carried out concerns a "classic" threat, but one you may still encounter, namely an infected file on a USB stick.

Once the USB stick is inserted into the PC, we find an executable file disguised as a PDF document. It's a traditional technique used to get the user to launch a malicious programme themselves. Microsoft Defender detects the threat immediately once the file is opened.

An antivirus like Bitdefender, on the other hand, immediately scans the USB stick when it is inserted into the device's USB port, detecting the threat before the file is even opened.

This antivirus has a feature for automatic scanning of removable media, very useful for minimising infected file threats.

Free antivirus vs paid antivirus: comparison table

Here is a comparison table on the tests carried out between the free antivirus for Windows and paid alternatives.

Microsoft Defender: when is it enough?

As you could see, Microsoft Defender passed two out of four of PrimeLicense's tests, offering good protection against various common threats.

Therefore, for careful and aware domestic use of your PC it proves sufficient, so you don't need to worry about the additional costs of antivirus software like McAfee or BitDefender.

To summarise, Microsoft Defender may be enough for you if:

• you browse mainly on websites you know
• you don't regularly use your PC for online banking
• the computer is not used by children or teenagers
• you don't manage client data and documents

The effectiveness of Microsoft Defender is also confirmed by independent AV-TEST tests, where in June 2026 Windows antivirus achieved the maximum score of 6/6 in the protection category.

When should you get a paid antivirus?

A paid antivirus is highly recommended if you use desktop PCs or laptops for your professional work in a company or as a freelancer. Likewise, you should get a paid antivirus if you do a lot of banking operations.

Therefore, you can consider purchasing one if:

• you work remotely or in smart working and want to protect sensitive files and data
• you frequently use online banking or investment platforms
• you have a VAT number and manage invoices or client data
• the computer is used by multiple people who download files
• you want to protect multiple devices

The difference is not only about virus detection. Depending on the suite chosen, commercial antivirus software such as McAfee and BitDefender can include dedicated tools against phishing, ransomware and dangerous sites, as well as additional features for privacy and browsing protection.

Frequently Asked Questions

We answer some of the most frequently asked questions about Windows' free antivirus.