SmartScreen

SmartScreen, officially Microsoft Defender SmartScreen, is a security feature developed by Microsoft to help protect Windows users from phishing, malware, and unsafe downloads. It is built into Windows operating systems and Microsoft Edge, and is also used by some Microsoft 365 applications. The service relies on a cloud-based reputation database to assess websites and downloaded files in real time, blocking or warning users about potential threats.

How it works: When a user navigates to a website, SmartScreen checks the site’s reputation against its database and known unsafe domains. If the site is flagged as risky, a warning is displayed or access is blocked. For downloads, particularly executable files, SmartScreen evaluates the file’s reputation; downloads with low or unknown reputation may be blocked or shown with a warning. The feature also prompts users when attempting to run or install apps from the internet, and can prevent installation of suspicious or unverified software.

History and branding: SmartScreen originated as SmartScreen Filter in Internet Explorer and was later integrated into Windows as Windows Defender SmartScreen. As part of Microsoft’s broader Defender branding efforts, it is now marketed as Microsoft Defender SmartScreen, with cross-product protection across Windows and Edge and ongoing improvements to its cloud-based reputation system.

Privacy and configuration: Microsoft states that telemetry is used to improve the service’s reputation data and may include device and usage information. Organizations can adjust or disable SmartScreen through policy settings in Windows Group Policy and via configuration options in Edge and Microsoft 365 apps.