We have changed the save system in Update 10. With the new system, if there is an issue with a world and the save gets corrupted, you will be able to go a few steps back and get the world back. Here is how it works and how you can use this feature to get your world back:
1. Click "Load World" in the Main Menu.
2. Go and click on the world you want to load an earlier version of.
3. Click the "World Backups" button.
4. Pick an earlier save and click "Load World".
Voilà! Even though you will lose the progress made between these saves, you will be able to get your world back. To minimize progress loss, try to save often.
P.S. This will not restore the inventory, health, hunger, or thirst to the old version. It will only restore the world/raft.