The truth behind Chrome’s 4GB “weights.bin” file for Gemini Nano

You may have recently seen viral PSAs floating around social media, such as this PSA thread by X user Pirat_Nation, warning that Google Chrome is silently downloading massive amounts of AI bloatware onto your computer. Some of these viral posts rely on fearmongering for engagement farming: While there’s some truth to the situation, there’s also a whole lot of context and nuance you should be aware of to properly understand what is happening and how you should react. The AI model is not spyware, and it isn’t a virus — in fact, it actually protects your privacy when you’re using AI features.

What is happening? Google Chrome is downloading a lot of data to your device, allegedly “without your consent”

If you navigate to your hard drive’s Chrome User Data folder (likely present under “C:Users<yourusername>AppDataLocalGoogleChromeUser Data“), you may discover a massive folder called OptGuideOnDeviceModel containing a large file named “weights.bin.” This file ranges from 3 to 4GB and has been silently downloaded by Chrome. If you delete/remove the file, Chrome will silently download it again when you restart the browser.

The PSA warning correctly notes that Chrome is “quietly” downloading this large file. However, Chrome has likely obtained your permission many moons ago (likely at the time of the browser’s installation) to download files it needs for its functioning, but many users claim there was no explicit permission granted to download this particular file on their computer.

If you’re wondering what this “weights.bin” file is, it is actually Gemini Nano, Google’s streamlined, on-device AI model. As part of Google’s push to integrate AI directly into the browser, Chrome relies on these “weights” to run generative AI features locally on your machine rather than relying entirely on cloud-based servers to process those AI requests.

When a user first interacts with a feature that relies on new AI-centric APIs, Chrome automatically downloads the foundational AI model directly to the user’s computer — provided the user’s computer meets these minimum requirements:

• OS: Windows 10 or 11; macOS 13 or later; Linux; Chrome OS on Chromebook Plus devices.
• Storage: At least 22GB of free space.
• CPU or GPU: Built-in models can run with a GPU or a CPU:
  • GPU: Strictly more than 4GB of VRAM
  • CPU: 16GB of RAM or more and four CPU cores or more.
• Network: Unlimited data or an unmetered connection for the initial model download.

You can check if the foundational model is already installed on your device by navigating to chrome://on-device-internals in Chrome’s address bar. Under the “Model Status” tab, you can see the model’s version, installation path, and exact folder size.

Is this a privacy violation? It’s actually the opposite of that

The sudden appearance of a massive, unknown file that gets redownloaded has understandably sparked privacy concerns, leading to inaccurate PSAs and misconceptions that user data is being secretly harvested.

To clear the air: Chrome’s built-in AI is actually designed to keep your data strictly on your device. Because the Gemini Nano model runs locally on your computer’s CPU or GPU, AI tasks are performed entirely on the client side. By downloading the AI foundation model (the 4GB file) directly onto your computer, Chrome can process your AI requests on-device without sending your private browsing data, text prompts, or summaries to Google’s cloud servers.

While an unmetered internet connection is required for the initial model download, subsequent use of the AI model does not require a network connection. Google explicitly states that no data is sent to Google or any third party when using the model.

Why users are (justifiably) frustrated

Even though the file isn’t malicious, the delivery method has frustrated many users. Chrome initiates this download completely in the background. There is no user consent prompt, no notification, and no warning that as much as 4GB of your computer storage is about to be occupied. For users on base-model laptops with 256GB SSDs, a silent 4GB background download can be a significant hit on their available storage space.

As mentioned, if you just find the folder and delete it, Chrome will silently redownload the 4GB file the next time you restart your browser. To the average user, the file appears forced, inexplicable, and inescapable.

If you don’t particularly care about using AI features in your browser, the frustration is even more justified. You’re downloading and storing an AI model file for no real benefit in such a situation.

How to disable Chrome’s AI model and reclaim your storage

I wouldn’t advise removing the AI model from your computer if you use AI features in Chrome, since on-device models are better for your privacy. However, if you don’t intend to use any AI features within Chrome, you can consider removing the AI model.

To permanently remove the file and stop Chrome from hoarding your storage, you must first tell the browser to stop fetching the model, and then delete the files.

Step 1: Disable the Chrome Flags

1. Open Google Chrome, type chrome://flags into your URL address bar, and press the Enter key on your keyboard.
2. In the search bar at the top, search for “optimization-guide-on-device-model.”
3. When the #optimization-guide-on-device-model flag appears, click the dropdown menu on the right and select “Disabled.”
4. Search and disable “#prompt-api-for-gemini-nano” too.
5. Click the Relaunch button that appears at the bottom of the screen to restart Chrome.

This stops Chrome from using the feature, preventing forced auto-downloads when you delete the files.

Step 2: Delete the Folder

Now that Chrome is blocked from retrieving the file, you can safely delete the bloated folder. Make sure Chrome is fully closed before doing this.

• On Windows:
  • Press Win + R.
  • Paste %LOCALAPPDATA%GoogleChromeUser Data and hit the Enter key on your keyboard.
  • Look through the “Default” folder (or your specific user profile folder) for the “OptGuideOnDeviceModel” folder.
  • Delete it.
• On macOS:
  • Open Finder.
  • Press Cmd + Shift + G.
  • Paste ~/Library/Application Support/Google/Chrome/ and hit the Enter key on your keyboard.
  • Search for the “OptGuideOnDeviceModel” folder and move it to the trash.
  • Empty your trash bin.

There’s a chance a future Chrome update will reset these flags and redownload the AI model. There are registry changes you can make to prevent this from happening, but that is outside the scope for most users. The easier, non-nuclear option would be to repeat these steps again.