~/Library/Application Support/Google/Chrome/OptGuideOnDeviceModel/2025.8.11.1/ is the folder.
Within it is a weights.bin that's 4GB.
Will I break anything if I delete that?
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asked Nov 20, 2025 at 23:29
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I don't think your answer to your question makes it go away completely at all. It'll definitely come back once you upgrade. The date subfolder it's in suggests it might even be redownloaded more often.
To get rid of it properly, for Windows there's a Chrome policy that can be modified - GenAILocalFoundationalModelSettings - to value 1 in the registry, or Do not download model in gpedit. I don't know about the macOS equivalent, but it should be a policy with the same name in theory.
I also found mentions of a bunch of various flags you can potentially disable to turn the whole feature off, e.g. chrome://flags/#optimization-guide-on-device-model, but I've seen at least 5 other ones mentioned in several sources, with various people claiming for each that they don't work, so yeah - I don't have this file and won't risk enabling anything to test it to avoid AI nonsense on my device.
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This file is the Gemini Nano large language model that powers the built-in AI features.
It's used by web APIs like the Prompt API, Translator API, Summarizer API, and sometimes Chrome DevTools.
Yes, according to my own experiments, you can delete the weights.bin file or the OptGuideOnDeviceModel folder. Chrome won't fatally break, but anything relating to the built-in AI will be kind of broken (probably) until you restart the browser.
There's some good developer documentation at The Prompt API.
If you want to go nerdy: You can open up chrome://on-device-internals/ and hit "Load Default" and do inference directly with the model.
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For macOS, run the following command in the terminal
defaults write ~/Library/Preferences/com.google.Chrome.plist GenAILocalFoundationalModelSettings -int 1
Check it on chrome://policy
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