Google has apparently been downloading a massive 4GB artificial intelligence model onto some users’ computers through its Chrome browser without clearly asking for permission first. The claim comes from security researcher Alexander Hanff, who says Chrome is silently installing a file linked to Google’s Gemini Nano AI system in the background on eligible laptops and desktops.
According to Hanff’s report, the browser first checks whether a device meets certain hardware requirements and then downloads the AI model automatically. The report suggests many users may not even realise the file exists until they notice missing storage space or unusually high data usage.
Hanff claims that the AI model is linked to Chrome’s on-device AI capabilities, including writing assistance and other AI-powered browser tools. However, he argues users are not clearly informed that a multi-gigabyte AI model is being stored locally on their machines. The report comes just weeks after Hanff raised similar concerns around Anthropic, where he alleged the company’s Claude Desktop app quietly installed browser integration components across multiple Chromium-based browsers and could even reinstall them after being deleted.
To test whether Google was indeed downloading the file through Chrome, Hanff said he carried out a controlled macOS test where he created a fresh Chrome profile and monitored filesystem activity logs. According to his findings, Chrome created a folder called OptGuideOnDeviceModel and downloaded the entire 4GB payload without any direct user interaction. He claimed the process took just over 14 minutes and that Chrome had already evaluated the machine’s hardware capabilities before the download began.
How to check for this Google file?
The report also claims that simply deleting the files may not permanently solve the issue. Hanff said Chrome can reportedly download the AI model again later unless certain experimental Chrome flags are disabled or the browser itself is removed. On Windows 11, users can reportedly check for the files inside the %LOCALAPPDATA%GoogleChromeUser Data directory under the OptGuideOnDeviceModel folder.
Another workaround mentioned in the reports is disabling the “Optimization Guide On Device” related flags through chrome://flags. However, some reports suggest uninstalling Chrome is the only guaranteed way to stop the files from returning.
While the issue raises privacy concerns, Hanff also highlights the broader cost of distributing such a large AI model at Chrome’s scale. He estimated that if hundreds of millions of Chrome users receive the 4GB download, the total data transferred could reach petabytes or even exabytes globally, leading to significant energy consumption and carbon emissions. The report argues this could particularly affect users on metered or expensive internet connections, where an unexpected 4GB background download may directly increase internet costs.
Notably, at the time of writing, Google had not publicly responded in detail to the allegations. For now, users concerned about storage or background AI downloads may want to manually check whether the AI model folder exists on their system, review Chrome’s experimental AI-related settings, and monitor future browser updates more closely.
