There is a maximum number of open files that the Macintosh Operating System will allow. This number can be anywhere between 291 to 340 files (not indexes or tracks, but individual files), depending on the CPU/O.S. configuration. MasterList CD can detect when this maximum number has been reached, but not until after you have added (opened) the audio files and attempt to play back audio from the MasterList window. If MasterList CD prompts you that you have exceeded the maximum limit, save your changes before quitting (it might be necessary to delete items until a Save is allowed).MasterList CD may crash or freeze the Mac when quitting under these circumstances.