I've been having this problem recently. My newest level was accidently saved to TSF, instead of 1.23. I can't think of an easy way of converting my level back to its original form. So I was thinking, is there a way to make a program that converts TSF files to 1.23? I'm not a programmer so I have no idea how to do this. But if there is a way, I think it would become very useful to not just me, but to everybody who made the same mistake I did, or just want to convert their level anyway.