Even if you aren’t using Google Gemini, it might be using your device. Security researcher Alexander Hanff, also known as “That Privacy Guy,” recently reported that Google’s widely used Chrome web browser is quietly storing an on-device AI model without explicitly asking for user permission.
According to Hanff, Chrome secretly stashes about 4GB of AI model files on Chrome users’ devices (though it should be noted that many users have been unable to find the file). The reported model is stored in a folder called OptGuideOnDeviceModel. The largest part of that folder is a file called weights.bin. Hanff claims that the weights are for Gemini Nano, Google’s lighter-weight, on-device version of its large language model.
Per the researcher’s findings, the Nano model is installed on any device that meets the minimum hardware requirements to host it. Google Chrome reportedly does not offer any prompt for the user to affirmatively agree to install the model, nor is there any setting to opt out or remove the files. If you track down the files yourself by parsing through Chrome’s install library, you can manually delete the model—but Hanff reported that it will automatically be redownloaded the next time you restart Chrome, without any indication that it’s happening. Hanff claims to have independently demonstrated this happening on both Windows and MacOS devices.
Gizmodo asked Google for clarification about the file. A spokesperson for the company explained, “We’ve offered Gemini Nano for Chrome since 2024 as a lightweight, on-device model. It powers important security capabilities like scam detection and developer APIs without sending your data to the cloud. While this requires some local space on the desktop to run, the model will automatically uninstall if the device is low on resources. In February, we began rolling out the ability for users to easily turn off and remove the model directly in Chrome settings. Once disabled, the model will no longer download or update.”
While Hanff has drawn more attention to the 4GB of unwanted AI weights, he’s certainly not the first to notice it. A number of people have called attention to the file over the last year or so across IT forums and online communities, most wondering what it is and asking how to get rid of it.
By all accounts, it does appear that the file is, in fact, an on-device version of Gemini Nano. And while Google certainly doesn’t appear to ask for permission to install its AI model on your device, it also doesn’t exactly hide that it’s happening—as long as you know where to look. According to Google’s own documentation, the on-device AI model is what is used for most AI-related tasks. There’s even an API that developers can access to use the on-device Nano model for AI-powered features.
The closest you’ll find to Google explaining this to the user is in Chrome’s terms of service. Within that text, Google states: “We’re constantly developing new technologies and features to improve our services. For example, we use artificial intelligence and machine learning to provide you with simultaneous translations, and to better detect and block spam and malware. As part of this continual improvement, we sometimes add or remove features and functionalities, increase or decrease limits to our services, and start offering new services or stop offering old ones. When a service requires or includes downloadable or preloaded software, that software sometimes updates automatically on your device once a new version or feature is available.”
So, what exactly can you do about the on-device AI model that Google is storing for you?
First, check to see if it is actually on your device. You can do this by visiting “chrome://on-device-internals” via the Chrome omnibar, where you’d enter a URL or search term. This will tell you the model is on your device and how much space it takes up.
From there, removal will depend on what is available in your browser.
If you are one of the users who have had the opt-out mentioned by the Google spokesperson rolled out to your browser, you can simply open Chrome, go to the Settings menu, select System, and choose “Turn On-device AI on or off.”
If you don’t have that option, there are some workarounds others have found. According to Hanff, you can enter “chrome://flags” in the Chrome omnibar and disable AI-related features to prevent it from automatically re-downloading the model once it is removed. Others have recommended changing the “weights.bin” file to read-only to prevent Google from re-installing it. It should be noted that some users have reported that deleting the AI model from Chrome can make the browser act a bit funky—and you definitely shouldn’t expect any of the AI-related features to function once you remove it.
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