Chrome users are finding a large local AI model on their PCs as Google expands on-device browser features.

Key takeaways

• Google Chrome may download a file of roughly 4GB called weights.bin to run Gemini Nano, Google’s on-device AI model for local browser features
• The file is usually stored in Chrome’s OptGuideOnDeviceModel folder and may return if deleted
• Gemini Nano is used for browser-managed AI capabilities, including local AI APIs and some Chrome features
• Users who do not want Chrome’s local AI model should disable On-Device AI in Chrome settings where available, rather than just deleting the file

Chrome users spot a mystery storage spike

Google Chrome users are urged to check their local browser files after reports that the desktop browser can store a 4GB AI model on Windows PCs and other supported systems.

The file, commonly identified as weights.bin inside an OptGuideOnDeviceModel folder, is tied to Gemini Nano, Google’s smaller AI model designed to run directly on the device rather than solely in the cloud.

Why Chrome is storing Gemini Nano locally

Google’s own developer documentation says Chrome’s built-in AI program uses browser-managed models, including Gemini Nano, to power local AI capabilities for websites, apps and browser features.

That approach can improve speed and privacy for some tasks because processing may take place locally. But the discovery has frustrated users who say Chrome did not clearly warn them about the download or its storage impact.

Deleting the file may not be enough

Manually removing weights.bin can free space, but users report the file may return if the related Chrome AI components remain enabled. Google’s enterprise policy documentation also indicates that, when local foundational model settings are allowed or unset, the model can be downloaded automatically.

Users who want to remove it should look for Chrome’s On-device AI controls in Settings, where available, or use managed policy options on business devices. Disabling the feature may also turn off some AI-powered Chrome capabilities.

Frequently asked questions (FAQ)

Why is Google Chrome downloading a 4GB AI file to your computer?

Chrome downloads the file to store Gemini Nano locally, allowing certain AI-powered browser features to run on your device instead of relying entirely on cloud processing. Google says Chrome’s built-in AI uses browser-managed modes, including Gemini Nano.

What is Google Gemini Nano Banana?

“Google Gemini Nano Banana” mixes up two Google AI names. Gemini Nano is the on-device AI model used by Chrome, while Nano Banana is the nickname for Gemini 2.5 Flash Image, Google’s image-generation and editing model.

Can I turn off AI in Google Chrome?

Yes. Google has added an On-device AI setting in Chrome, and disabling it should prevent Gemini Nano from running locally. Simply deleting weights.bin may not be enough because Chrome can download the model again if the feature remains enabled.

Is Chrome’s 4GB ‘weights.bin’ file spyware?

No, Chrome’s weights.bin file is not spyware. It is a local AI model file associated with Gemini Nano, which Chrome uses for on-device AI features. The concern is understandable, however, because a multi-gigabyte file appearing without clear user-facing notice or consent can feel invasive.