Hi guys. This just happened to me and I lost about 5 hours worth (2 days) or work.
I made
3 mistakes, specially considering I should know better.
Mistake number 1.
Let one day go by without versioning. That would have cut my losses in half.
Then, java (or stencyl) got slow. Maybe it ate too much memory (Windows 7 x64 will open java's appetite) and was feeling too fat.
It never happened before with stencyl. Whatever, I saved my work. I saved it again. I tried to shut it down. It asked me save again (here comes the second one).
I said yes. If I had it saved, I should have left it at that. But I wasn't thinking.
It took forever and a half to save (are you feeling number 3 coming up around the corner?). I waited. Then I tried to shutdown stencyl while it was saving. Then I waited about three whole seconds.
I shutdown my computer without the game beig completely saved (nobel prize for human error please). I ended up with a corrupt data.xml.
With this true tale, I bid farewell to you.
To one and all, I ask you to take heed, Augustus himself bestowed it upon posterity:
Festina lente. (more haste, less speed).