I've had sunvox for a long time now, more than three years. And I update around 6 times a year now (used to be bi-weekly). Updating to last months update did not do anything strange, like not starting. But I have no idea which version I had before the current one, I assume I skipped one.
What I did see is that I had 2 sunvox pnd's one lowercase, and one propercase, I've removed the old one (2015) and sunvox just started normally. I removed, then reinstalled the application, and when I restored the previous session, the old song was there, so nothing out of the ordinary.
I once saw a directory turn into a file, but that was for another pnd, and I had to move the appdata away to make it work.