I made a PowerPoint presentation with PP 2011 for Mac, and went through and narrated it. After narration, I could go through the entire presentation and hear my voice. I saved the file and closed it. When I opened it later, there was still the narration icon under each slide, but no sound. I have replicated this issue with other presentations. Narrations record and work fine, until you close the file and open it again. How do I save the sound? I ran a search for any .wav files and found nothing in my entire user directory. Narration timings also seem to work correctly, just no audio.
It ended up being that the file was being saved as a ppt, not a pptx. So powerpoint would allow you to record a narration but it wouldn't save the audio.