when I turned on Minecraft, it said Minecraft crashed.

Put the summary of the bug you're having here
When I logged on to Minecraft, it said Minecraft crashed.
What I expected to happen was...:
Describe what you thought should happen here

What actually happened was...:
Describe what happened here

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