Can't launch/open minecraft/

Put the summary of the bug you're having here
So I opened minecraft I saw the update and I said "Okay I just need to click play and done" but it doesn't open it says "Preparing..." no percent shows up

What I expected to happen was...: I open it and play like usual
Describe what you thought should happen here
They should fix it/

*What actually happened was...:*I opened minecraft and it doesn't let me play it keep rendering as in "Preparing"
Describe what happened here
It won't start

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