Microsoft is retiring Word's Similarity Checker on 3 October 2026, removing the built-in plagiarism and originality detection tool from Microsoft Editor. The feature, which scanned text against online sources and returned a similarity percentage so users could add citations or rewrite content, is being cut as Microsoft says it wants to focus on capabilities more widely used across Word. Organisations relying on it for checking originality will need to find alternative tools, though Word's citation, spelling and grammar functions remain untouched.

Launched in 2020 and powered by Bing Search, Similarity Checker compared user text against web sources to flag potential plagiarism. Microsoft 365 Copilot and other editing tools are unaffected by the withdrawal, though Microsoft has explicitly stated Copilot is not designed to serve as a formal similarity or plagiarism-validation tool. The company hasn't published usage figures, but its framing suggests the feature saw limited adoption, and its removal sits somewhat awkwardly against Microsoft's heavy recent push to embed Copilot AI features throughout Office.