OS: Windows 7 (ver 6.1, arch x86)
Java: 1.8.0_73 (by Oracle Corporation)
Launcher: Minecraft Launcher 1.6.61 (bootstrap 4)
Minecraft: 1.10.1 (updated Wed Jun 22 11:14:48 BST 2016)
Put the summary of the bug you're having here
The world was clicked and should have loaded ready to play.
The game loaded the world for a few seconds before crashing the game.
Some worlds do load correctly and can be played, the world that crashed was a survival world and is the only one to do this so far.