Who hasn't been able to play since the May 6th Build? I've tried making my Library folder visible and deleting all files except the Steam Apps folder, then reinstalling (several times). I've tried upgrading from 10.7.8 to 10.8.3 and then re-setting all of my certificates and running Keylogger. I've tried turning off my Firewall, making sure Steam is accepted on my Firewall. I've tried changing my router settings.
All I get when I start the program is "Updating Steam..." and "Looking for available updates..." then it just sits there forever.
Any other ideas? Putting in a trouble ticket has been useless and, after all, according to Steam/Valve, you're my tech support.