Minecraft-Crashing

Put the summary of the bug you're having here

*What I expected to happen was to open normally.
Describe what you thought should happen here: it should open normally.

*What actually happened was my Minecraft crashed when it was done dowloading.
Describe what happened here: When I pressed play it finished downloading then it crashed.

Steps to Reproduce:
1. Open Minecraft
2. Press play
3. Wait for it to be done downloading.