Lost Audio in Presenter 13

I know this has been asked before, but here goes again.  What causes Presenter to lose the embedded audio when the development files are moved?  How can we recover without having to re-embed audio for every page?

We move our completed projects to folders on a network drive.  If a revision is needed, we copy them back to the hard drive for editing.  It often happens that the audio gets "lost" in this move back and forth.  

I hope someone can explain what causes this, and has a solution or at least a work-around to fix the issue.  This particular course has 100 + audio files in both slides and interactions and the spent in reconnecting audio will be far greater than the time invested to make the minor revisions needed.

I appreciate the help,

Darrell