I broke Gridmap, badly!

So as the title states, i broke gridmap... I tried to create a custom map from it using the editor and saving it under a new name (which now wont open wasting nearly 3 hours but thats not the point here). This, however, has caused gridmap to be flat and covered in just sand with nothing there. I decided to extract the original to the "levels" folder in my documents, which brought things back, except the sand is still there, the water section has only 2 levels of depth instead of the usual 5...

I broke Gridmap, badly!