I discovered a very easy way to corrupt save files on the Xbox version. Here are the steps to reproduce:

1. Go into the Nether, wander a fair distance from your portal, die (I am good at this piece).
2. After you die, choose to exit to the main menu (don't respawn), confirm that you want to quit.
3. When you attempt to reload the world, the Generating World\Building Terrain screen will go to a full bar (100%) and then nothing else happens. The world appears to be corrupt.

I have reproduced this issue with a new world using the steps above. No packs are loaded (vanilla).

None of these steps have worked to recover the world:

1. Copy the world, new copy fails similarly.
2. Tried to load the world into Realm, it fails to load.
3. Tried to switch the world to Creative, still will not load.
4. Uninstall\reinstall Minecraft, no change.
5. Deleted my local saves, redownloaded from the cloud, no change.