How to Remove Chrome’s Hidden 4GB AI Storage (weights.bin)

Users on Windows, macOS, and Linux have recently discovered a massive file taking up nearly 4GB of local disk space. The file, named weights.bin, is hidden deep within Chrome’s user directory.

This file contains the local machine learning weights for Gemini Nano, Google’s on-device large language model. Chrome silently downloads this multi-gigabyte package to power features like “Help me write,” automated tab organization, and local page summaries.

What if you do not want to use this ondevice model, or do not have storage tpo spare?

Simply deleting the file does not work; Chrome’s background update manager will immediately re-download it. To permanently reclaim your storage space, you must disable the underlying AI systems in the browser.

Step 1: Find the weights.bin File on Your System

The local model is stored inside a specific directory named OptGuideOnDeviceModel. You can verify its existence by checking the following default paths:

• Linux: ~/.config/google-chrome/Default/OptGuideOnDeviceModel/
• macOS: ~/Library/Application Support/Google/Chrome/Default/OptGuideOnDeviceModel/
• Windows: %LOCALAPPDATA%\Google\Chrome\User Data\Default\OptGuideOnDeviceModel\

Note: If you use multiple Chrome browser profiles, check each profile folder, as Chrome can download the model dynamically for each eligible profile.)

Step 2: Turn Off the “On-Device AI” Setting

Google provides a standard toggle to disable local model deployments, though its availability can vary depending on your browser version and region.

1. Open Chrome and click the three vertical dots in the top-right corner, then select Settings.
2. Click on the System tab in the left-hand sidebar.
3. Locate the setting labeled On-device AI (or Enable optimization guide on device).
4. Turn the toggle switch Off.

If this toggle automatically removes the folder, your process is complete. If the toggle is missing from your menu, proceed to the alternate flag configuration below.

Step 3: Disable the Backend Chrome Flags

If the main settings toggle is unavailable, you must force-disable the internal component updater via experimental flags to prevent the browser from pulling the 4GB file back from Google’s servers.

1. Type chrome://flags into the address bar and press Enter.
2. In the top search bar, type optimization guide.
3. Locate the flag named Enables optimization guide on device (#optimization-guide-on-device-model).
4. Change the drop-down menu setting from Default or Enabled to Disabled.
5. Next, search for Prompt API and set both Prompt API for Gemini Nano and OnDeviceModelBackgroundDownload (if visible) to Disabled.
6. Click the blue Relaunch button at the bottom of the window to restart Chrome.

Step 4: Delete the Leftover Model Directory

Once the flags are disabled, Chrome will no longer attempt to update or re-fetch the model assets. You can now safely delete the folder to clean up your drive.

1. Fully close Google Chrome.
2. Open your system’s file manager and navigate back to the path specified in Step 1.
3. Select the OptGuideOnDeviceModel folder and delete it completely (or empty your recycling bin/trash).