How to Remove Google Chrome's Stealthy 4GB AI Model from Your Mac (and PC)

Overview

If you own a 2020 M1 MacBook Air—or any computer with limited storage—you might be alarmed to discover that Google Chrome has been quietly downloading a >4GB AI model called Gemini Nano onto your machine without asking. The file, weights.bin, is part of Chrome’s plan to run AI features locally (like smart writing and editing), but it can feel like an unwelcome storage hog—especially if you never use those features. This guide explains exactly how to remove it, step by step, and covers the surprising pitfalls that most online advice misses. We’ll focus primarily on macOS (where the issue is most studied), but also cover Windows 11. By the end, you’ll have a clean drive and control over what Chrome stores on your computer.

How to Remove Google Chrome's Stealthy 4GB AI Model from Your Mac (and PC) — Source: www.fastcompany.com

Prerequisites

A computer running macOS or Windows with Google Chrome installed (version 126 or later, where Gemini Nano first appeared).
Administrator privileges on your machine (to delete files and change system settings if needed).
Basic familiarity with Chrome’s settings and flags page (we’ll explain everything).
Knowledge of your Chrome version — go to chrome://settings/help to check. The toggle we want is gradually rolling out; the version number matters.
An external backup (always wise before messing with browser files).

Step-by-Step Instructions

1. Try the Official Toggle First (The Simple Way)

Google recently added an "On-device AI" toggle in Chrome settings. If your Chrome version (e.g., 148 as of this writing) has it, you can remove Gemini Nano with one click.

Open Chrome and type chrome://settings in the address bar.
Go to Privacy and security → On-device AI (if you see it).
Toggle the switch off — this will immediately delete the model and prevent future downloads.
Close and reopen Chrome to ensure the change sticks.

Note: This toggle is only present in newer Chrome versions on Windows 11 (and some macOS builds). Many Mac users still lack it. If you don’t see “On-device AI” in settings, proceed to the next method.

2. Manually Delete the Model File (And Prevent Re‑download)

Simply deleting weights.bin is useless—Chrome recreates it. You must also disable the feature that triggers re‑download.

On macOS

Locate the model file: Open Finder, press Cmd+Shift+G, and paste this path: ~/Library/Application Support/Google/Chrome/GeminiNano/
You should see weights.bin (4+ GB). Drag it to Trash.
Prevent re‑download via flags: Type chrome://flags, search for #gemini-nano and set it to Disabled. Also search for #optimization-guide-on-device-model and set it to Disabled.
Restart Chrome.

On Windows 11

Open File Explorer and paste: %LOCALAPPDATA%\Google\Chrome\User Data\GeminiNano
Delete weights.bin.
In Chrome, go to chrome://flags, disable the same flags as above.
Restart Chrome.

Important: After disabling the flags, Chrome should no longer fetch the model. But some users report the model reappears after an update—so check periodically.

3. Use a Script to Block the Download (Advanced)

If the flags don’t work (they often fail), you can block the download at the network level or by replacing the file with a dummy.

Option A: Replace weights.bin with an Empty File

Delete the original weights.bin as above.
Create a new empty file named weights.bin (using Terminal on Mac: touch ~/Library/Application\ Support/Google/Chrome/GeminiNano/weights.bin).
Set the file permissions to read-only to prevent Chrome from overwriting it: chmod 444 /path/to/weights.bin.

Option B: Block the Download URL

Use a hosts file entry or a firewall rule to block optimization.gemini.google.com. This is more involved but stops the download entirely. The exact domain may vary; monitor network activity.

4. Prevent Future Updates from Re‑installing the Model

Chrome updates can revert your changes. To keep Gemini Nano off after an update:

Disable automatic updates (not recommended for security).
Use a launch agent or scheduled task that deletes weights.bin and reapplies flags every time Chrome starts.

Common Mistakes

Only deleting weights.bin — Chrome will re‑download it almost immediately. You must also disable the feature.
Relying on the “On-device AI” toggle — It’s not available in all Chrome versions yet. Check your version before assuming it works.
Ignoring the flags — Many online guides say to disable #gemini-nano but forget the optimization model flag. Both must be disabled.
Not restarting Chrome after changes — Settings and flags only take effect after a restart.
Assuming the model is gone after an update — Chrome updates often re‑enable the flags. Re‑check periodically.
Using a system cleaner — Some tools may delete the model but also delete flag settings.

Summary

Google’s Gemini Nano model can eat over 4GB of your drive without warning. The easiest fix is the “On-device AI” toggle, but it’s not yet on all Macs. Your next best bet is to manually delete the file and disable two Chrome flags (#gemini-nano and #optimization-guide-on-device-model). If that fails, replace the file with an empty one or block the download domain. Check after each Chrome update to ensure the model stays gone. With these steps, you’ll reclaim your storage and control over what Chrome installs.