Put the summary of the bug you're having here

What I expected to happen was for Minecraft to load

What actually happened was Minecraft did not load, and was stuck on the "preparing" part of the loading bar.

Steps to Reproduce:
1. Load the new Minecraft launcher on a mac.
2. Click play for any version of Minecraft
3. Minecraft does not load.

Here is a link to a Minecraft forum thread about other people having this issue: http://www.minecraftforum.net/forums/support/unmodified-minecraft-client/2696301-minecraft-launcher-stuck