Google Chrome has been secretly downloading a 4GB artificial intelligence model called Gemini Nano onto user devices without asking permission, and the company doesn't tell people it's there. The file, named weights.bin, sits deep inside Chrome's user profile directory and powers on-device AI features like "Help me write" and scam detection. Users cannot find any checkbox in Chrome Settings to control this download because no such option exists.

What Is Gemini Nano and Why Is Google Installing It?

Gemini Nano is a smaller version of Google's Gemini AI model designed to run directly on your device rather than sending data to Google's servers. The model performs tasks such as detecting scam phone calls, helping you write text messages, summarizing recordings, and analyzing Pixel phone screenshots. Google says the on-device approach protects privacy by keeping your data local instead of uploading it to the cloud.

However, security researcher Alexander Hanff, known as "That Privacy Guy," discovered the silent installation and raised serious concerns.

"Running inference on users' own hardware allows them to push 'AI features' without the compute costs," Hanff told CNET.

Alexander Hanff, Computer Scientist and Privacy Researcher

In other words, Google may be shifting the computational burden from its own expensive servers onto your personal device to reduce its infrastructure costs.

How Did This Happen Without User Consent?

Chrome users will not know they have Gemini Nano unless they actively search for it, because Chrome did not ask and does not surface the installation in any visible way. The download happens automatically if your device meets the hardware requirements, such as sufficient processing power, RAM memory, and storage space.

The environmental and data impact is staggering. At Chrome's global scale, pushing 4GB to hundreds of millions of devices generates between 6,000 and 60,000 tonnes of carbon dioxide equivalent emissions, roughly equivalent to the annual output of a small wind farm. In many parts of the world, 4GB represents an entire month's mobile data allowance, yet Chrome consumes that in one unrequested download.

When users try to delete the weights.bin file to reclaim storage space, Chrome treats the deletion as an error and automatically re-downloads the entire 4GB package again. The only permanent ways to prevent reinstallation require disabling AI features through technical settings like chrome://flags or enterprise policy tools that most home users do not possess.

What Are the Legal and Privacy Concerns?

Privacy experts argue that Google's approach may violate European regulations. Hanff suggested the installation could breach the European Union's General Data Protection Regulation (GDPR) principles of lawfulness, fairness, and transparency. The ePrivacy Directive explicitly prohibits storing information on a user's device without prior, informed, and unambiguous consent.

The situation raises additional concerns because Chrome functions perfectly well without the 4GB on-device model, so no "strictly necessary" exemption applies. Furthermore, the most visible AI feature in Chrome's address bar, labeled "AI Mode," does not even use the on-device model; those queries go straight to Google's servers instead. This means the 4GB installation imposes costs on users with no offsetting privacy benefit.

Steps to Check for and Remove Gemini Nano

• Locate the file: Open your file manager (File Explorer on Windows, Files on Chromebooks, or Finder on Macs) and search for a folder called OptGuideOnDeviceModel. Inside that folder, look for a file called weights.bin, which is where Gemini Nano lives.
• Disable through Chrome settings: Go to Chrome settings and look for the option to turn off and remove the model directly. Google began rolling out this ability in February, allowing users to disable the model so it will no longer download or update.
• Use the flags method: Type "chrome://flags" into your browser address bar, find "Enables optimization guide on device," and turn it off to prevent future downloads.
• Apply Windows 11 Registry policy: If you use Windows 11 Pro, you can navigate to the Registry Editor and set the "GenAILocalFoundationalModelSettings" value to 1 under HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome to block the model from downloading and remove any previously installed version.
• Uninstall Chrome entirely: The most drastic option is to uninstall Chrome completely, though this removes the browser entirely rather than just the AI model.

What Does Google Say About This?

A Google spokesperson told CNET that Gemini Nano will automatically uninstall if the device does not have enough resources, such as processing power, RAM memory, storage space, or network bandwidth. The company also stated that the weights.bin file powers important security capabilities like scam detection and developer APIs without sending data to the cloud.

However, critics argue that Google should have been transparent about the installation from the start. Hanff suggested that Google likely avoided asking for permission because doing so would hinder their ability to push the model and whatever comes after it. The lack of transparency has drawn backlash from privacy advocates and regulators who question whether global tech corporations are exempt from consent statutes that have been on the books since 2002.

What Happens Next?

The controversy highlights a growing tension in the AI era: companies want to deploy AI features at scale, but users increasingly demand control over what runs on their devices. Regulators are now facing questions about consent laws and silent AI deployments, particularly in Europe where data protection rules are stricter. The situation may force Google and other browser makers to reconsider how they roll out on-device AI features in the future, balancing innovation with user transparency and environmental responsibility.