Steamnesia won’t launch.

[El Mariachi]

Do any other steam applications have this issue? Have you tried re-installing the Steam application itself? And have you rebooted your computer?

Yes, I've completely wiped and reinstalled Steam, and rebooted. Amnesia was the only Mac game I had installed on there, but now I've downloaded Torchlight and it exits with an error window: "Steam must be running to play this game (SteamAPI_Init() failed)." System log says only that it exited with exit code 1.