Romfs builder isn't perfect, so things like this happen occasionally. You could try making sure your running an up to date version of .NET and see if that fixes it, but I don't have any other advice as far as getting romfs builder to work. If you can't get it to save, you could always try using another program for building the romfs, but you'll need to find make sure whichever program you use can handle Japanese file names.I moved the rom files completely onto my computer, but It still freezes at the save prompt without bringing it up. I'm using the file Downloads\Game#\Romfs_ when choosing it from the directory. Instead of saving the builder just freezes without bringing it up