WarmPlace.ru

Just like the title says, if you name a saved file ".sunvox", it won't save it, but SunVox will think it is saved under that name, and will prompt you to save it as ".sunvox" if you just do an ordinary save (and not a Save As) after that point. I'm on the latest version of SunVox.

The dot at the beginning of the file name means it's a hidden file.
So the ".sunvox" will be successfully saved, but then you will not see it in the list of files :) You can find it only through the system file manager with "show hidden files" option enabled.