The game crashed whilst initializing game The game crashed whilst initializing game Error: i: Non [a-z0-9/._-] character in path of location: minecraft:blocks/iron_bars3D

Have suddenly received the following crash message when trying to start Minecraft..

 

The game crashed whilst initializing game
The game crashed whilst initializing game
Error: i: Non [a-z0-9/._-] character in path of location: minecraft:blocks/iron_bars3D

 

Crash report attached