Chrome has been running an experiment on its users’ hard drives. Since at least April 2026, the browser has been automatically downloading Gemini Nano, Google’s on-device AI model, to eligible desktop and laptop computers without prompting users, notifying them or offering a straightforward way to opt out. A Chrome data folder most people have never opened powers a set of AI features, including scam detection and text assistance and reinstalls itself if removed through standard means. Privacy advocates say the practice raises serious questions about consent. Here’s how to find the file and what your options actually are for getting rid of it.

The mysterious file in question is Gemini Nano, an AI model that runs on devices, such as smartphones and laptops rather than in the cloud. According to Alexander Hanff, a Swedish computer scientist and lawyer known as That Privacy Guy, it’s been installed on some Chrome browsers without permission. You won’t know when it’s been downloaded onto your device, either. 

Hanff said Gemini Nano will only be installed if the device meets the hardware requirements. It’s still unknown how many people have gotten the install.

Gemini Nano performs tasks such as detecting scam phone calls, helping you write text messages, summarizing recordings and analyzing Pixel phone screenshots. It’s not to be confused with the AI Mode pill in the address bar. If you use AI Mode, your queries are routed to Google Gemini servers, not to Gemini Nano.

A Google spokesperson told CNET that Gemini Nano will automatically uninstall if the device doesn’t have enough resources, such as processing power, memory, storage space or network bandwidth. 

“In February, we began rolling out the ability for users to easily turn off and remove the model directly in Chrome settings,” the spokesperson said. “Once disabled, the model will no longer download or update.”

Google gives more information about on-device generative AI models in Chrome on this web page.

How to get rid of the AI model 

If you want to remove the 4GB AI model from your device, first check whether it’s installed. 

Hanff said Chrome users will not know they have Gemini Nano unless they search for it, because “Chrome did not ask” and “Chrome does not surface it.”

The easiest way to remove Gemini Nano from your device is to uninstall Chrome.

On a Mac

1. If you’re using a Mac, open Finder by clicking the blue smiling face icon on the far left of the dock.
2. Then, click Go in the top menu bar and hold the Option key so that Library appears in the dropdown menu. 
3. Click Library, then navigate to Application Support > Google > Chrome > Default. See if there’s a folder called OptGuideOnDeviceModel. If the folder exists and contains a file named weights.bin, the AI model was installed.
4. To permanently remove it on a Mac, open Chrome and click the three-dot menu in the top-right corner. Then click Settings, then System and toggle off On-device AI.

On a Windows device

If you’re running a Windows device, there are a few ways to check whether Gemini Nano is installed.

1. One way is via a Run Command. Press the Windows key and R, paste in %LOCALAPPDATA%\Google\Chrome\User Data\OptGuideOnDeviceModel and then press Enter. If that file comes up, see if weights.bin is in there.
2. You can also use File Explorer to check whether the AI model is installed. Navigate to C:\Users\[YourUsername]\AppData\Local\Google\Chrome\User Data\OptGuideOnDeviceModel and look for weights.bin.
3. To get rid of the AI model in Windows, open Chrome, navigate to Settings > System, and toggle off On-device AI. While still in Chrome, type chrome://flags in the address bar and search for Optimization Guide. Then, set Enables Optimization Guide on Device to Disabled.
4. Then restart Chrome by completely closing it, using the menu to exit, not just closing windows.
5. Finally, delete local files by navigating to \AppData\Local\Google\Chrome\User Data and deleting the OptGuideOnDeviceModel folder.

Watch this: Google I/O 2026: New Gemini, Smart Glasses and a Whole New Laptop OS. Here’s What to Expect

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Why does it matter?

Hanff said the push might be intended to help Google cut costs by moving AI work off its own servers and onto your computer.

“Running inference on users’ own hardware allows them to push ‘AI features’ without the compute costs,” Hanff told CNET.

AI inference is the process by which the model actually does the things you prompt it to, as opposed to the training of it, which generally happens in a data center. If it’s happening on your computer instead of in the cloud, that could have an impact on things like your computer’s speed or battery life, in addition to storage space the model’s taking up on your hard drive.

But Hanff suggested there could be legal ramifications, at least in Europe. He suggested that the Gemini Nano install could constitute a breach of the European Union’s General Data Protection Regulation’s principles of lawfulness, fairness and transparency. Hanff said that, considering the potential environmental impacts, Google should have announced it under the Corporate Sustainability Reporting Directive.

“Google has given us every reason not to trust them with a history spanning two decades of global privacy violations at massive scale,” Hanff told CNET. “So, I suspect they figured asking permission (what the law requires) would hinder their ability to push this model and, of course, whatever comes after it.”