Privacy researcher and computer scientist Alexander Hanff has documented that Google Chrome silently installs a 4GB AI model on users' devices without consent. While auditing a Chrome profile created for automated privacy checks, Hanff discovered a folder named OptGuideOnDeviceModel containing 4GB of model files called weights.bin — despite the profile never receiving any human input.
The model is Google's Gemini Nano, a lightweight on-device large language model. Hanff's evidence shows Chrome downloaded the 4GB file in 14 minutes and 28 seconds on April 24, 2026, without a consent prompt, a settings notification, or a checkbox. Multiple independent reports across Windows, macOS, and Linux confirm the file reinstalls automatically when restarted after deletion.
Chrome's AI Mode Actually Sends Queries to the Cloud
Chrome 147 displays an "AI Mode" pill in the address bar. Users might reasonably assume it routes queries to the local on-device model. According to Hanff's investigation, that assumption is wrong. The AI Mode pill is a cloud-backed Search Generative Experience that sends every query to Google's servers. The on-device Gemini Nano powers right-click menu features that most users never access.
Snopes verified the claim as mostly true, finding the weights.bin file on three of six staffers' devices, spanning both macOS and Windows machines. Google told Snopes it began rolling out an opt-out option in Chrome settings in February 2026, though the setting was not available to all users.
Legal and Environmental Risks
Hanff argues the practice likely violates the EU's ePrivacy Directive, which governs storage of data on user devices, and GDPR transparency requirements. Those claims have not been tested in court. He also calculated that at Chrome's roughly one-billion-device scale, distributing the 4GB file generates between 6,000 and 60,000 tonnes of CO2-equivalent emissions.
The Malwarebytes security blog noted a similar pattern weeks earlier when Hanff documented Anthropic's Claude Desktop silently installing browser integration files across multiple Chromium browsers without meaningful user disclosure, also arguing those installs likely violated EU law. As crypto.news reported, AI-driven security and privacy risks are accelerating in 2026, with CertiK warning that AI tools are making attacks faster and harder to detect across the digital ecosystem.