Audio sent from Final Cut Pro 5 to the Soundtrack Pro audio Waveform Editor may go offline in Final Cut Pro after you finish editing or processing the audio clip. If this happens, you will need to reconnect the media in Final Cut Pro. Please see the Final Cut Pro User's Guide for more information on reconnecting disconnected media.
Tip: You can prevent this from occurring by making sure Soundtrack Pro has finished saving the file before switching to Final Cut Pro.