old_contents: import os
  import platform
  
  
  class Command(object):
      def __init__(self, mpf_path, machine_path, args):
          del mpf_path
          if platform.system() == 'Windows':
              os.system('start "MPF Core" mpf mc {} {} -p'.format(
                  machine_path, ' '.join(args)))
              os.system('start "MPF Media Controller" mpf game {} {} -p'.format(
                  machine_path, ' '.join(args)))
  
          else:
              if os.fork():
                  os.system('mpf game {} {}'.format(
                      machine_path, ' '.join(args)))
              else:
                  os.system('mpf mc {} {}'.format(
                      machine_path, ' '.join(args)))
  
new_contents: import os
  import platform
  import subprocess
  
  
  class Command(object):
      def __init__(self, mpf_path, machine_path, args):
          del mpf_path
          if platform.system() == 'Windows':
              subprocess.Popen('mpf game {} {}'.format(machine_path,
                                                       ' '.join(args)))
              os.system('mpf mc {} {}'.format(machine_path, ' '.join(args)))
  
          else:
              if os.fork():
                  os.system('mpf game {} {}'.format(
                      machine_path, ' '.join(args)))
              else:
                  os.system('mpf mc {} {}'.format(
                      machine_path, ' '.join(args)))
  
subject: Change "both" launch command on windows to use Popen instead of separate windows