What is SmartScreen?

SmartScreen is Microsoft's content filtering technology that analyzes messages for spam, phishing, and malware characteristics. Originally developed for Internet Explorer to detect dangerous websites, SmartScreen expanded to email filtering across Microsoft's consumer and business email platforms.

SmartScreen examines message content, sender reputation, link destinations, and attachment characteristics. It uses machine learning trained on billions of messages to identify patterns associated with unwanted or dangerous mail. The technology updates continuously as Microsoft encounters new threat patterns.

For email senders, SmartScreen's content analysis means that spammy language, suspicious links, or patterns matching known attacks can trigger filtering regardless of sender reputation. Even legitimate senders face SmartScreen challenges if their content resembles spam or phishing attempts common in Microsoft's data.