Could it be that you have installed chromium both from ubuntu packages and from the snap, by any chance?
Can you share the output of the following command, run in a terminal? xdg-settings get default-web-browser ** Changed in: chromium-browser (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to chromium-browser in Ubuntu. https://bugs.launchpad.net/bugs/1754833 Title: Chromium complains that it's not the default browser when it is the default according to Gnome Settings Status in chromium-browser package in Ubuntu: Incomplete Bug description: (As seen in a daily build of Ubuntu Budgie 18.04 32bit downloaded earlier today) See attached screenshot. Thanks, Ken. *** To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/chromium-browser/+bug/1754833/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : email@example.com Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp