Everytime you open an media file, it will opens with Itunes or Quicktime Player. What if i want to be open always with a third party app? (Like Vlc for example). Of course you can always make right clic , " Open With " and select the desire player...thats one way. BUT, you can set Vlc as default player for CERTAINS filetypes like this way. Right clic onto a avi file. Select " Get info " option. Go to " Open with " tab and select the media player you want. Then clic " Change All... " button (That will associate avi file types with Vlc). Thats all! Note:This works for avi files, dunno with others filetypes.