java.lang.NullPointerException: Initializing game

Put the summary of the bug you're having here

What I expected to happen was...:
We expected the game to launch.
What actually happened was...:
We received the following error....

java.lang.NullPointerException: Initializing game
at ave.a(SourceFile:674)
at ave.ar(SourceFile:560)
at ave.am(SourceFile:361)
at ave.a(SourceFile:310)
at net.minecraft.client.main.Main.main(SourceFile:124)

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...