I’ve never seen a root password being asked for Brave on Ubuntu. There’s something strange going on.
Let’s double-check a few things first:
- Are you logged in as root or as a regular user?
- When you see the prompt, does it ask for your user password or for the root user’s password?
- Did you install using the official Brave repository (https://brave.com/linux/#debian-9-ubuntu-1604-and-mint-18) or the Snap package (https://snapcraft.io/brave)?