Protect your PC from unwanted software

Applies to: SecurityWindows 10

Sometimes when you install new apps, you might also inadvertently install unwanted software. In some cases, this software will be installed without adequate consent and perform actions that you did not authorize. This software behavior can unexpectedly impact your experience using your PC. These apps might display advertising, modify your browser settings, and install bundled software.

These are some of the common scenarios of unwanted software on your PC:

  • An app prompts you that it is installing, but there's no obvious way for you to opt out or modify the settings of the installation.
  • Advertisements display in modified search results pages or websites.
  • Your browser settings are modified without you doing anything; for example, your home page or shortcuts are changed or plug-ins are installed.
  • Your web search results or other online activities are monitored for the purpose of displaying certain types of ads to you.

Minimize the possibility of unwanted software getting onto your PC

  • Make sure you're running Windows Security (or Windows Defender Security Center in previous versions of Windows 10). 
  • Use Microsoft Edge as your browser, because it allows plug-ins only from Microsoft Store. However, both Microsoft Edge and Internet Explorer use Windows Defender SmartScreen, which helps block these apps.
  • Download apps only from trusted sources, such as Microsoft Store.

If you believe you have unwanted software

  • Turn on Windows Security for Windows 10. If the unwanted software persists, you can submit the files to Microsoft.
  • Uninstall software you don’t need using Add/Remove Programs.
  • In Windows Security, get the latest definitions and then run a full scan with Windows Security. Learn how.
  • Perform an offline scan with Windows Defender Offline.

If you're in an enterprise, see the Windows Defender Security Intelligence website for in-depth information about unwanted software.