Google Chrome silently installs 4 GB AI model on users' PCs

Google Chrome has been automatically downloading a hidden 4 GB file named weights.bin, which contains the Gemini Nano on‑device AI model. The file resides in the hidden OptGuideOnDeviceModel folder and is used to power features such as writing assistance, page summarisation, tab organisation and scam detection. The download occurs without user consent or notification, triggered only when Chrome detects that a device meets undisclosed hardware criteria. The behaviour was uncovered by privacy researcher Alexander Hanff and confirmed on Windows, macOS and Linux systems. Users can stop the download by disabling the “AI on‑device” option in Chrome’s Settings; deleting the file alone prompts Chrome to restore it, though a registry edit on Windows can block future downloads.

The discovery has raised privacy concerns because the large model consumes significant disk space and is installed covertly across many Chrome installations worldwide.