Put the summary of the bug you're having here
I expected the launcher to work like the old one did.
After it loaded, it displayed "Welcome, 1999Brock!" above the "Log Out" and "Play" buttons. I hit Play, and a bunch of things starting with Client> came up. The main things I noticed were "Client> Invalid memory access of location 0x0 rip=0x0" and "Game ended with bad state (exit code 139)".
1. Open the launcher.
2. Click "Play"
Related issues
duplicates
Comments

Upgrade to OS X 10.6, follow the comments of MCL-90.