The short answer
Usually, after a check. Might hold something you care about. Look inside before removing it.
What is it?
On Macs that meet its hardware requirements, Google Chrome downloads Gemini Nano, a small language model used for built-in AI features, into ~/Library/Application Support/Google/Chrome/OptGuideOnDeviceModel. The model file is often around 4 GB.
A model Chrome downloads for its built-in AI features. Deleted, it comes back unless on-device AI is turned off in Chrome.
What happens if you delete it?
If you only delete the folder, Chrome downloads the model again while its on-device AI features are turned on.
How to remove it properly
In Chrome, open Settings › System and turn off on-device AI; Chrome then removes the model itself. Deleting the folder by hand only helps while that setting is off. Where the setting is missing in your Chrome version, the model is managed through chrome://flags or policy.
From the app itself: Chrome > Settings > System: turn off on-device AI, then Chrome removes the model.
Before you delete it
Chrome features that rely on the local model stop working until it is downloaded again.
How MoreRoom helps
MoreRoom recognises this item and labels it “Review first”: it shows what’s inside, its size and last use, so you can decide. Nothing is removed without your say, and everything goes to the Trash first, with Undo.
Frequently asked questions
Can I delete Chrome’s OptGuideOnDeviceModel (Gemini Nano)?
Usually, after a check. Might hold something you care about. Look inside before removing it. If you only delete the folder, Chrome downloads the model again while its on-device AI features are turned on.
Will Chrome on-device AI model (Gemini Nano) come back after I delete it?
Yes. If you only delete the folder, Chrome downloads the model again while its on-device AI features are turned on.
How do I remove Chrome on-device AI model (Gemini Nano) properly?
In Chrome, open Settings › System and turn off on-device AI; Chrome then removes the model itself. Deleting the folder by hand only helps while that setting is off. Where the setting is missing in your Chrome version, the model is managed through chrome://flags or policy.