Privacy researcher Alexander Hanff has uncovered that Google Chrome is quietly installing a 4GB AI model called Gemini Nano on users’ computers without their knowledge. While investigating an automated privacy audit profile, Hanff found that Chrome had downloaded the model files—stored as weights.bin in a folder named OptGuideOnDeviceModel—without any human interaction. The download completed in under 15 minutes on April 24, 2026, and the model automatically reinstalls if deleted, as confirmed on Windows, macOS, and Linux systems.
Despite Chrome 147 introducing an “AI Mode” in the address bar, Hanff discovered that this feature actually sends queries to Google’s cloud servers for Search Generative Experiences, not the local model. The on-device Gemini Nano only powers obscure right-click menu options that most users never use. Snopes verified the claim, finding the weights.bin file on three out of six staff computers across both macOS and Windows. Google stated it began rolling out an opt-out setting in February 2026, but it wasn’t available to everyone.
Hanff argues that this silent installation likely violates the EU’s ePrivacy Directive and GDPR transparency rules, though no court has tested these claims yet. He also calculated that distributing the 4GB file to Chrome’s billion users could generate between 6,000 and 60,000 tonnes of CO2-equivalent emissions. Similar concerns were raised by Malwarebytes about Anthropic’s Claude Desktop installing browser integration files without disclosure. As unsolicited data collection grows, transparency failures continue to erode user trust across digital platforms.