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Chrome downloaded a multi gigabyte AI model to your Mac: OptGuideOnDeviceModel explained

Chrome can download its on-device AI model, a folder of several gigabytes, without asking. Where it is, what uses it, and how to stop it coming back.

5 min read

Look inside Chrome's data folder and you may find OptGuideOnDeviceModel, holding a file named weights.bin of several gigabytes. It is the on-device AI model Chrome downloads to power features that run locally, such as writing help, scam detection and page summaries. Reports put the folder at around 4 GB.

Check whether you have it

du -sh ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel 2>/dev/null
ls -lh ~/Library/Application\ Support/Google/Chrome/OptGuideOnDeviceModel/*/ 2>/dev/null

Chrome only downloads it on machines that meet its requirements, so many Macs will not have it.

Removing it, and keeping it removed

Deleting the folder on its own does not work for long: Chrome downloads the model again. Turn the features off first.

  1. In Chrome, open Settings, System and look for the on-device AI option. Turn it off. (Where it appears varies between Chrome versions.)
  2. Quit Chrome completely.
  3. Move the OptGuideOnDeviceModel folder to the Trash.
  4. Start Chrome and check after a few days that the folder has not returned.

Organisations that manage Chrome can block the download with the GenAILocalFoundationalModelSettings policy, which is the most reliable method. Chrome flags also control it, but flags reset after major updates.

The rest of Chrome

Chrome keeps other downloaded components and per profile caches beside it. See Chrome components and Chrome taking up space. Other browsers built on the same engine may download similar models, covered in Chromium browsers.

Common questions

What is OptGuideOnDeviceModel in Chrome?

It is the folder where Chrome stores its on-device AI model, used for features such as writing help, scam detection and summaries. Its weights.bin file is several gigabytes.

Can I delete Chrome's weights.bin file?

Yes, but Chrome downloads it again unless the on-device AI features are turned off first. Turn them off in Chrome's settings, quit Chrome, then remove the folder.

How do I stop Chrome downloading its AI model?

Turn off on-device AI in Chrome's System settings. Managed Macs can block it with the GenAILocalFoundationalModelSettings policy, which is the most reliable method.

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