Microsoft has never claimed that Windows Defender is all you need. The company has offered the application as a backup to full suite security products like Avast Free Antivirus. Avast works closely with Microsoft as a top partner in the Microsoft Virus Initiative (MVI), with both companies collaborating to test each other’s antimalware tools.
If you have an antivirus product installed, Windows Defender switches to standby mode while your primary tool gets the job done. Otherwise, without a recognized antivirus program, Windows Defender steps up and assumes the role of primary security application. Without question, Windows users have always needed an application to protect against computer viruses, spyware, and other malware.
It's not that Windows is especially prone to viruses or that Windows is an insecure operating system. Microsoft has done an excellent job of locking it down, reducing the attack surface — the total amount of attack vectors, or opportunities — and responding quickly to serious security breaches. Windows is the target of malware writers because it commands more than 90% of the desktop PC market.
It's like the old saying attributed to bank robber Willie Sutton, who said he robbed banks because that's where the money is. If you want to steal bank login credentials, you go after Windows users.
Is Windows Defender only available on Windows 10?
Under the name Windows Defender, the antivirus application is only available on Windows 8, Windows 8.1, and Windows 10 computers.
However, the same software utility has been available for several years. For Windows XP, the software was released as Microsoft Security Essentials. You may also have encountered it under that name in Windows Vista and Windows 7. While the application was not built into those operating systems, it was available as a free download.
The original Windows Defender was an anti-spyware program on Windows XP, Windows Vista, and Windows 7, and Microsoft Security Essentials was created to fill in the gaps. Now, Windows Defender is back as a full-fledged antivirus tool.
What does Windows Defender do?
The latest version of Windows Defender — the one built into Windows 10 — is billed as a full antivirus solution. It promises real-time protection and browser integration to protect you from malicious websites. Windows Defender also scans your Outlook mailbox for suspicious attachments.
For a long time, Microsoft Defender was a serious laggard in comparative tests by AV Test, the gold standard in antivirus evaluation. In the past year, when it comes to standard antivirus detection, Microsoft closed the gap with the subscription-based antivirus products.
But the key word is “standard.” The primary focus of Defender is computer viruses. While people tend to use the terms "malware" and "viruses" interchangeably, they are not the same. Malware refers to all malicious software, and viruses are just one type. For example, ransomware is also a form of malware, but it is not a virus.
In addition to malware, there are other issues to watch out for online — such as phishing scams and fraud — which fall under the larger category of threats.
Are there any limitations?
While Windows Defender has improved its virus detection rate in recent years, it's not without limitations. To begin with, it doesn't catch as many different forms of malware as leading third-party antivirus solutions do.
Windows Defender only targets viruses while also providing some web browser and email protection. The built-in software doesn't catch other threats such as ransomware, nor does it catch all browser exploits. In short, it's good for one form of malware, but leaves users vulnerable to many others.
Windows Defender also lacks a centralized logging and alerting system. There is no log of scans to tell you what was found or when your last scan occurred, which means you cannot confidently determine the last time your computer system was checked. The result is that users are not always aware of new threats or protected against them.
Another downside is you have to use Windows Update to manually download new definitions — database entries of new viruses so that Windows Defender can detect them. All of the major antivirus programs automatically update themselves in the background, usually multiple times per day, protecting you against new threats as they emerge.
How does Avast Antivirus compare?
So how does Windows Defender compare against Avast Free Antivirus? Windows Defender handles the basics pretty well. It runs various types of scans, checks file downloads, and comes with a firewall.
Recent tests show Microsoft closed the accuracy gap with other antivirus programs, but it still has shortcomings. Windows Defender is not as good at catching phishing and ransomware, its browser security is limited to Edge (which it is in the process of abandoning in favor of Chrome), and it returns false positives more often than the competition.
Meanwhile, Avast Free Antivirus has a wide range of advanced security features that combine for 360-degree protection, including:
Wi-Fi Inspector monitors your home network for any vulnerable devices.
AutoSandbox executes files in isolation for 15 seconds to make sure they’re safe.
CyberCapture forwards downloaded files to Avast for detailed threat analysis.
Behavioral Shield watches your software for any signs of a malware infection.
Web Shield and Mail Shield protect you against threats in your network traffic or inbox.
In recent tests conducted by AV-Comparatives, Windows Defender detected 99.5% of known malware and 96.3% of the zero-day malware. Avast Antivirus detected 100% of both zero-day and known malware.
Avast is also less demanding on your computer’s resources, according to AV-Comparatives. Avast had significantly less impact on system performance than did Windows Defender. No one wants an antivirus program slowing down their system.
Avast Free Antivirus is the ultimate way to detect malware and other threats on a Windows system.
So, is Windows Defender really enough?
Windows Defender is good enough if you use the internet minimally, and if you rely only on Windows' own tools. (Occasionally, malware is passed along via a USB drive, but the vast majority of infections come from internet activity.)
Windows Defender is also good enough to serve as a backup should your antivirus subscription run out and you are unable to renew. That is Windows Defender's role: It's a backup in lieu of a proper antivirus product.
For more extensive browsing, especially if it reveals your sensitive personal data like online shopping or banking, you should rely on a third-party antivirus to provide more extensive protection. Remember, viruses aren’t the only thing to watch out for — different malware strains, phishing scams, and other threats can compromise your privacy and security.
Pair Windows Defender with the ultimate third-party antivirus
It's good to know Microsoft has your back, but Windows Defender should always remain a secondary option. It's there if you need it, but only as a temporary stopgap. Avast Free Antivirus has a much bigger and broader threat-detection network, protecting you against a wider variety of threats than Windows Defender.
With Avast Free Antivirus, you’re covered against the full spectrum of malware along with many of the most common infection vectors — Wi-Fi vulnerabilities, misbehaving or out-of-date software, phishing attacks, and more. These are just some of the many ways Avast protects the privacy and security of over 400 million people around the world.