Cannot Launch Minecraft

Each time I go into the launcher to launch minecraft and click play the launcher gets stuck on preparing and makes no progress after a few seconds my laptop freezes and I have to force my laptop to shutdown so I am able to continue using it. I've been playing minecraft on my computer for an very long time and this just happened all of a sudden without me messing with settings or anything. I have tried uninstalling the launcher and reinstalling yet it didn't work. I play on mac.