Why (and not) to turn off Windows Defender completely

Microsoft provides Windows Defender, a built-in antivirus program that is completely free of charge for Windows 10 and Windows 11. The program is regularly updated to identify any malicious software attempting to run on the computer. Despite its reliability, many users opt to use third-party antivirus solutions.

In certain circumstances, due to its deep integration within the system, Windows Defender may not be the best option. If you are considering disabling Windows Defender (it cannot be uninstalled), there are reasons both for and against doing so that you should be aware of.

deactivate Windows Defender

  • Install other antivirus. When installing an antivirus in Windows, it is important to deactivate Windows Defender first. Installing another antivirus as a complement to Windows Defender can cause problems, as both antiviruses may conflict and scan all the files we download from the Internet, websites we visit, and our computer in real-time, which can significantly affect our PC’s performance.
  • Problems with old applications. There are many older applications that have not been updated for a long time and are not signed by developers authorized by Microsoft. As a result, when attempting to download such an application, the system detects that it is not signed and automatically blocks the download. However, we can easily reverse this process by accessing the message that the system shows us.
  • Improve privacy. Antiviruses are primarily designed to safeguard our computer against various types of threats and not necessarily ensure our privacy. To ensure that our computer is well-protected, we must grant the required access permissions to the antivirus, whether it is Windows Defender or any other antivirus software available.


Windows Defender is a native antivirus program in Windows that offers a significant performance advantage, especially on older computers where system performance is crucial to provide the best user experience. This factor alone may be sufficient to determine whether to disable Defender on Windows.

Moreover, Defender works in conjunction with the Windows firewall, another native tool that operates alongside it. If we install a third-party antivirus application, the control of the firewall in Windows will be handed over to the antivirus we install. This will lead to a significant reduction in performance on older computers, thus adversely impacting the user experience.