I had a similar problem before using RDP remote desktop. I was successful when I actually took an existing .wav file from the Unity, brought that to my desktop, rerecorded the message, and then reloaded it. I think that had something to do with not having the correct settings for the .wav file. The easiest fix for me was to take an existing one and copy over it. Don't know if that will help, but free to try it.
