If you've recently noticed a mysterious folder eating up 3–4 GB of disk space inside your Chrome profile directory, you're not alone. The culprit is OptGuideOnDeviceModel — a folder Chrome creates to store AI model files for its Optimization Guide feature.
We will answer on this question:
What Is Chrome's OptGuideOnDeviceModel Folder (and Can You Delete It)?
What Is It?
Chrome's Optimization Guide downloads machine learning models locally so it can run AI-powered features directly on your device — things like on-device summarization, smart suggestions, and Gemini Nano integration. These models are stored as large weights.bin files and can grow to several gigabytes over time.
On Ubuntu (and other Linux systems), you'll find the folder here:
~/.config/google-chrome/Default/OptGuideOnDeviceModel/
or, if you use multiple Chrome profiles:
~/.config/google-chrome/Profile 1/OptGuideOnDeviceModel/
Is It Safe to Delete?
Yes. Deleting this folder is safe and won't break Chrome or affect your browsing. You'll only lose locally-processed AI features — everything else works normally.
The catch: Chrome treats this as an "essential component" for those features, so it may re-download the models automatically the next time you use Chrome. To prevent that, you'll want to disable the underlying flags first.
How to Remove It Permanently
Step 1 — Disable the flags:
- Open Chrome and navigate to
chrome://flags - Search for "optimization guide on device" → set to Disabled
- Search for "prompt API for gemini nano" → set to Disabled
- Click Relaunch to restart Chrome
Step 2 — Delete the folder:
- Close Chrome completely
- Run the following in a terminal:
rm -rf ~/.config/google-chrome/Default/OptGuideOnDeviceModel/
If you have multiple profiles, check for the folder under Profile 1, Profile 2, etc. as well.
The Bottom Line
The OptGuideOnDeviceModel folder is Chrome quietly downloading gigabytes of AI model weights to your machine — without much fanfare. If you're not using Chrome's on-device AI features, or if you're running low on disk space, it's completely safe to disable the flags and delete the folder. Just make sure to disable the flags first, or Chrome will simply download it all again.