Windows Defender

Anti-spyware that protects against slow performance and pop-ups


838 Votes

  • Category Anti-spyware
  • Program license Free
  • Version 7.0
  • Size 5.16 MB
  • Works under: Windows XP / Windows 7 / Windows 8 / Windows Vista / Windows 10
  • Program available in English
  • Program by Microsoft

Windows Defender is a powerful antivirus program for Windows-based computers. Windows Defender became the official Microsoft-approved antivirus program, replacing Windows Security Essentials for Windows 8 and later versions. As such, it is well-supported by Microsoft and well-integrated with the Windows operating system. Windows Update, often scheduled to run automatically, will automatically update virus definitions for Windows Defender. They can alternatively be downloaded and installed manually from within the program window.

There are many well-known free antivirus solutions, but as Windows Defender has increased in power with regular updates, it has surpassed many of these programs in effectiveness. While different virus and malware scanners will always detect viruses and malware differently, tests have shown that on average Windows Defender detects malware and viruses just as well if not better than many well-known free antivirus solutions. In fact, many paid antivirus solutions do not perform as well as Windows Defender and are not kept as up-to-date with timely virus definitions.

One feature that Windows Defender was long lagging behind on was support for boot-time scans. Many viruses launch themselves at Windows startup time and prevent antivirus programs from detecting them either by hiding themselves or preventing the antivirus program from running. Some other free antivirus solutions included the ability to run a boot-time scan, scanning every file on the hard drive before any viruses or startup programs had had the ability to run. For a long time, Windows Defender users had to be content with running Windows Defender in Safe Mode which may still not prevent virus interference. However, the most recent version of Windows Defender has added support for boot-time scanning with Windows Defender Offline. Scheduling this scan will reboot your computer and run a 15-minute scan of any programs that could be starting at runtime. This allows for the detection and elimination of many particularly nasty viruses and malware.

Windows Defender has its own quarantine and virus removal capabilities and allows the flexibility for users to specify exclusions (folders or files not to be scanned). This feature can be used either to prevent the deletion of false positives or to prevent a glitch which has been noted on some computers where the scanner engine becomes stuck scanning its own executable file and consumes large amounts of processor time. Real-time protection can also be toggled on or off, as can automatic sample submission. This allows for a great deal of flexibility.


  • It is entirely free!
  • Easy to download, install, and use.
  • Windows Defender is the official Windows antivirus solution, so it is updated automatically with Windows Update.
  • Timely, regular updates of definitions delivered straight from Microsoft.
  • There are many support articles online and good support from Microsoft.
  • As powerful as any other free antivirus program.
  • Allows for flexible scan types and scheduled scans.
  • The newest version has added support for boot time scans (Windows Defender Offline).


  • Windows Defender may not detect what some other programs consider malware.
  • Windows Defender may not be as powerful as some paid antivirus programs.
  • Windows Defender has an occasional glitch on some computers which causes the program to consume large amounts of processing time.
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