I am having the same problem. I have just bought a new PC and followed NCH instructions to re-install my old version of Express Scribe Pro 8.26 onto the new machine. Registration was successful and the program works fine but now ES doesn't even see my m4a files any more. However, I have found that if I drag the m4a files from their folder and drop them onto the ES startup icon they load into the software no problem and I can play them. It's a workaround but very irritating to have to do this extra step.
