BuddyPress.org

Deactivate BuddyPress and BP plugins, test registration and check DB wp_users table, does registration generate 2 rows for that new user? At this point, I do recommend restarting from scratch – delete htaccess file and drop DB tables and re-upload WP files manually i.e. via FTP or cpanel. – got to have a good solid WP/BP foundation moving forward.