Launcher will not load

The new launcher downloaded onto my computer this morning. I opened it, expecting to get the usual rectangular launcher window with update information and the "Play" button.

Instead, a square window labeled "Minecraft Launcher" opened. Inside the window it said "Loading." Two hours later, it still said "Loading." I have quit and restarted Minecraft multiple times. I have restarted the computer as well.

I am NOT getting a crash or any kind of bug report. The application does NOT hang. It just launches a square window that says "Loading." It is otherwise very quiet.

To reproduce: Um ... Open the new launcher in OSX 10.10.5? That's all I had to do to get the problem.

Thanks!