I am using Premier Elements 18. I also use a sound converter programme NCH Switch Sound Converter which converts sound files. For some reason when I save a movie in Premiere Elements 18 it is saving as a Switch Sound Converter file.
It tells me when I save the file it is saving as a Premier Elements File but it then saves as a sound file.
Building on John's question.... What is your workflow? I looked up "NCH Switch Sound Converter". It is not a "plugin". The website says that it is an independent program. They say it will extract an audio file from a video file but that is outside of and independent of Premiere Elements. I can't see where Premiere Elements could save or export a file using a format from an independent third party software provider.