How to Identify and Delete Chrome's Hidden 4GB AI Model on Mac

The Problem: Chrome's Unwanted 4GB AI File

If you've noticed your Mac's available storage dwindling without any obvious cause, your Google Chrome browser might be the culprit. Recently, security researcher Alexander Hanff uncovered that Chrome has been quietly downloading a 4GB AI model file—called weights.bin—onto eligible Macs without explicit user consent. This file powers Google's on-device Gemini Nano AI, which enables features like scam detection, autofill suggestions, and the Help Me Write tool. While these capabilities can be useful, the storage cost is steep, especially considering the lack of transparency about the download.

How to Check if the File Is on Your Mac

Before taking action, confirm whether the weights.bin file is occupying space on your system. According to reports, the file began appearing after Chrome updated to version 148.0.7778.97. Follow these steps to locate it:

1. Open Finder and click Go in the menu bar.
2. Hold the Option key and select Library from the dropdown.
3. Navigate to Application Support → Google → Chrome → Default.
4. Look for a folder named OptGuideOnDeviceModel.

If that folder exists and contains a file called weights.bin, the AI model is installed. Right-click the file and choose Get Info to verify its size. If you don't see the folder, you can rest easy—Chrome hasn't downloaded the model to your Mac.

How to Remove the 4GB File for Good

Simply deleting weights.bin from the Chrome library folder won't solve the problem permanently; Chrome is likely to re-download it the next time you launch the browser. To stop it for good, you need to disable Chrome's on-device AI features:

1. Open Chrome and click the three-dot menu in the top-right corner, then choose Settings.
2. In the left sidebar, click System.
3. Toggle off On-device AI.

Once this setting is disabled, Chrome will remove the model and should cease downloading it in future updates. Note that turning off this feature will also deactivate any Chrome functions that rely on it.

If the Toggle Is Missing

If you don't see the On-device AI toggle in Chrome's Settings, it may not have propagated to your version yet. In that case, type chrome://flags into Chrome's address bar and disable any AI-related flags you find. Then manually delete the weights.bin file using the steps in the previous section. After that, if you still have concerns about consent, consider switching to a different browser.

Why This Matters

The core issue is not just the 4GB storage hit—though that's significant—but the lack of transparency. Google downloaded a large AI model to millions of Macs without a clear prompt or opt-in. While the Gemini Nano features may benefit some users, others would prefer to keep their drive space intact. By following the steps above, you can reclaim that storage and regain control over your system.