Chrome quietly downloads AI files: How to find & delete AI data on Mac

If you use Google Chrome 117+ on macOS 13 Ventura or newer, a 4 GB AI model tends to appear on your Mac without asking. The file is Gemini Nano, Google’s on-device LM, and it shows up without a notification or consent, which raises concerns among users.

In this post, I’ll explain how to check whether this affected your Mac, how to remove the model files, and why deleting them may not be enough to keep them gone.

Remove AI and regular apps easily

Apps no longer come alone. AI models, caches, support files, and hidden data can stay on your Mac long after the app itself is gone. Instead of digging through Library folders manually, use App Cleaner & Uninstaller, which helps clear both the app and its related files, visible and hidden, completely without the file hunt.

App Cleaner & Uninstaller

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What AI data Chrome downloads and why

Chrome 117 introduced Gemini Nano, Google’s compact language model, running locally on your device. Starting with Chrome 147, two flags that trigger the download are on by default:

• #optimization-guide-on-device-model

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• #prompt-api-for-gemini-nano

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If Chrome has an internet connection, more than 2 GB of free space, and launches after updating to a compatible version, the model can download automatically without any user action. It doesn’t matter whether you used the said AI features or not.

On macOS, Gemini Nano currently works only on Apple Silicon Macs (M1-M5) running macOS 13 Ventura or newer. Intel-based Macs are no longer supported and do not receive the local AI model download.

What Gemini Nano is used for

Gemini Nano comes with a few Chrome AI features:

• Writing assistance
• Webpage summarization
• Smart paste
• Tab group suggestions
• On-device scam detection
• Prompt API for extension developers

On my MacBook Pro M1 (Tahoe 26.4.1) with Chrome 148, the file structure was like that:

~/Library/Application Support/Google/Chrome/OptGuideOnDeviceModel/
└── 2025.8.11.1/ ← model version
├── _metadata/
├── manifest.json
├── on_device_model_execution_config.pb
└── weights.bin ← main weights file measured 4.27 GB

Two smaller companion models often appear in the same directory:

• OptGuideOnDeviceClassifierModel/

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  – a separate content classifier

• OnDeviceHeadSuggestModel/

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  – address-bar suggestions

• optimization_g…e_model_store/

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  – metadata storage

Why Google downloads Gemini Nano automatically

Google’s position: local processing keeps data on your device instead of sending it to the cloud, AI features work offline, and responses arrive faster without a network round-trip.

The practical drawbacks users report:

• Takes 1.5-4+ GB without consent or notification
• No built-in cancel option or progress indicator
• Redownloads after deletion, even with AI flags disabled
• Chrome sometimes keeps multiple model versions, reaching up to 12 GB total (Chrome does not always remove the previous model versions)

How to check if Gemini Nano is on your Mac

I’ll show you three ways to verify whether Chrome has already downloaded the model.

Method 1: Finder

1. Open Finder.
2. Press Command+Shift+G.
3. Paste

   ~/Library/Application Support/Google/Chrome/

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4. Press Return.
5. Look for the folder

   OptGuideOnDeviceModel

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6. Right-click it → Get Info → check the size.

Method 2: Terminal

1. Open Terminal.
2. Check if the folder exists by running:

   ls ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel/

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   If the command returns a version folder name like

   2025.8.11.1

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   , the model is present.
3. Check its size with this command:

   du -sh ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel/

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4. Check all AI-related Chrome folders at once by entering the following command:

   du -sh ~/Library/Application\ Support/Google/Chrome/Opt*

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Method 3: Chrome

1. Open Chrome.
2. Go to

   chrome://components/

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   .
3. Look for Optimization Guide On Device Model.
   • It shows the installed version and download status.

chrome://components/

How to remove Gemini Nano from Mac

Removing the model files frees 4+ GB of disk space. Chrome will redownload the model on the next launch unless you also disable the AI flags. And even then, this workaround isn’t a guarantee of holding across updates.

Remove Chrome AI files manually in Finder

1. Quit Chrome completely:
   • Press Command+Q in the app, or
   • Open Activity Monitor → search for

     Chrome

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     → select all related processes → click X to stop them.
   
2. Locate Gemini Nano folder:
   • Open Finder.
   • Press Command+Shift+G.
   • Paste

     ~/Library/Application Support/Google/Chrome/

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   • Press Return.
   • Locate

     OptGuideOnDeviceModel

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     → select it → move it to Trash with Command+Delete.
   
   • Also, remove these folders, if any:

     • OptGuideOnDeviceClassifierModel/

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     • OnDeviceHeadSuggestModel/

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3. Empty the Trash.
4. Disable AI features in Chrome.
   1. Start with disabling the flags:
      • Open Chrome.
      • Go to

        chrome://flags/

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      • Set each of these to Disabled:

        • #optimization-guide-on-device-model

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          → Enables optimization guide on device

        • #prompt-api-for-gemini-nano

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          → Prompt API for Gemini Nano

        • #summarizer-api-for-gemini-nano

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          → Summarizer API for Gemini Nano

        • #writer-api-for-gemini-nano

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          → Writer API for Gemini Nano

        • #rewriter-api-for-gemini-nano

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          → Rewriter API for Gemini Nano
        • Click Relaunch.

   2. Set the On-device AI toggle to off:
      • Open Chrome.
      • Go to Settings.
      • Open the System tab in the left panel.
      • Disable On-device AI.

GenAILocalFoundationalModelSettings

Remove Gemini Nano using Terminal

If you are a tech-savvy user, this method is for you. It works on all macOS versions.

ls

1. Open Terminal.
2. Quit Chrome first:

   killall “Google Chrome”

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3. Verify the model folder is there before deleting:

   ls ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel/

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4. Delete the Gemini Nano folder:

   rm -rf ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel/

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5. Confirm deletion (empty output means success):

   ls ~/Library/Application\ Support/Google/Chrome/ | grep OptGuide

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6. After deleting, turn off the AI features in Chrome as instructed above.

Remove Gemini Nano with Chrome altogether using the uninstaller

If you want to uninstall Gemini Nano with Google Chrome, App Cleaner & Uninstaller shows Chrome’s complete storage footprint, 9.88 GB on the test machine, a significant share of which comes from AI components. This utility helps you delete that completely in a couple of clicks:

1. Download → run App Cleaner & Uninstaller.
2. Find Google Chrome in the app list → click it.

   Optional

   Switch to the Expert mode → check out the right panel, which shows all associated files and folders with sizes. The

   ~/Library/Application Support/Google/Chrome/

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   entry is where AI components live, including

   OptGuideOnDeviceMode

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   .

   

3. Click Uninstall or Remove (in Expert Mode) → confirm.

Chrome isn’t the only browser storing hidden AI data

Chrome handles local AI models differently from its other browsers. Here’s how four major browsers compare on Mac to that end.

Chrome is the only browser among the four that downloads a multi-gigabyte local model without explicit user consent or a reliable standard-setting opt-out.

Microsoft Edge uses the same Chromium architecture as Chrome, but provides more transparent policy controls, including an option to block and remove AI models entirely.

Opera is the lightest option: its AI runs entirely in the cloud, so it does not consume gigabytes of local storage.

Brave is the most user-respectful browser. Local models are never downloaded unless the user explicitly chooses to connect one through Ollama or another compatible server.

How much space can hidden browser data take?

OptGuideOnDeviceModel

Check in Terminal how much space browsers use

1. Open Terminal.
2. Run the following commands at once:

   du -sh \
   ~/Library/Application\ Support/Google/Chrome/ \
   ~/Library/Application\ Support/Microsoft\ Edge/ \
   ~/Library/Application\ Support/BraveSoftware/ \
   ~/Library/Application\ Support/com.operasoftware.Opera/

Final reveal

OptGuideOnDeviceModel

chrome://flags/