Chrome silently installs 4 GB Gemini Nano AI model without user consent

Google Chrome has been silently installing a 4 GB Gemini Nano on‑device AI model on every machine that meets hardware requirements, without any user consent or opt‑out UI. The model, stored as weights.bin in the user profile under OptGuideOnDeviceModel/2025.8.8.1141, is downloaded automatically when Chrome’s AI features are active by default. Deleting the file triggers an immediate re‑download; the only way to stop it is to disable the OnDeviceModelBackgroundDownload flag or apply an enterprise policy. The download occurs in a 14‑minute 28‑second batch that also includes a security update and a preload refresh, and is carried out by the com.google.Chrome.chrome_chrome_Unpacker_BeginUnzipping subprocess. Chrome logs the event in the OS‑level fseventsd file, showing the exact timestamps on 24 April 2026. The silent installation violates GDPR principles of lawfulness, fairness, and transparency, and breaches the ePrivacy Directive, while also creating a significant environmental footprint. The model powers features such as “Help me write” and on‑device scam detection, but users have no way to opt out unless they disable AI features via flags or enterprise policy. This incident represents a major privacy and security breach that affects all Chrome users worldwide.