# File lib/googleauth/credentials_loader.rb, line 148
      def from_system_default_path scope = nil, options = {}
        options = interpret_options scope, options
        if OS.windows?
          return nil unless ENV["ProgramData"]
          prefix = File.join ENV["ProgramData"], "Google/Auth"
        else
          prefix = "/etc/google/auth/"
        end
        path = File.join prefix, CREDENTIALS_FILE_NAME
        return nil unless File.exist? path
        File.open path do |f|
          return make_creds options.merge(json_key_io: f)
        end
      rescue StandardError => e
        raise "#{SYSTEM_DEFAULT_ERROR}: #{e}"
      end