When switching game versions from Minecraft snapshot 14w03b to Minecraft Version 1.7.2 ALL inventories will be wiped including chests and mine-carts. This bug only happens to worlds that were loaded in the snapshot. Note- I was using Optifine-A9 IN 1.7.2, but optifine is not needed for the bug

What I expected to happen was for my inventory to be the same and nothing to change. I went into the snapshot to use the new enchanting system expecting nothing to happen wrong. And for my inventory to stay the same

What actually happened is that I went into the snapshot. Loaded my world, to do some enchanting. Once I finished the enchanting. I switched back into 1.7.2 and all of my inventories were wiped.

Steps to Reproduce:
1. Load a world in 1.7.2
2. Get something in your inventory.
3. Close the World
4. Load The world in 14w03b
5. Close the world and launcher
6. Re-open the Launcher
7. Set the game version to 1.7.2
8. Load the same world you loaded in the snapshot
9. Your inventory will be cleared along with all chests.