hi,
we would like to continue correspondence on this issue via email, please send an email to the Switch Mac developer Chris.
just to clarify, the software's behaviour does not change after you register it, what you see in the demo/trial is exactly what you get after a purchase - there is simply nothing in the code to make it behave like you said. additionally, the latest version in particular has gone through extensive testing and it works fine on our Mac machines here (and yes that includes after we registered them).
in the email you send to us, you need to clarify to us what you mean when you say "it won't work at all for any conversions", that is a very general statement and could mean any number of things. you need to say what you are specifically doing with the software and what happened when you tried doing that. for example, you might say "i was converting from wave to flac, and the software gave the error message "cannot convert file". give us as much information as you can, because that will ultimately lead to faster problem resolution. if you have any example audio files that gave problems when converting them, giving us one of them would also be a great help towards narrowing down the cause of the problem.