This extension blocks incognito tabs. It must be allowed to run in incognito mode to work. See the readme for instructions on allowing it to run in incognito: https://github.com/brismuth/incognito-blocker/blob/master/README.md#allow-it-to-run-in-incognito This extension is open source: https://github.com/brismuth/incognito-blocker This is the entirety of the code that is running: chrome.tabs.onCreated.addListener((tab)=>{ if (tab.incognito) { chrome.tabs.remove(tab.id); } });