There is a bug in 10.32r1 Steam Edition - some kind of interaction between Steam and Gizmo causes Gizmo to crash. Since Gizmo is loaded on startup, this means users of popular add-ons like Skymaxx Pro can't fly. We are working on this now and I am hopeful we'll have some kind of fix tomorrow. I'll also post more details about the bug once we have more info. The crash affects X-Plane 10.32r1, Steam edition on OS X only, as far as we know. In the meantime: if you get a crash on start with X-Plane 10.32r1, please file a bug. Please include your Log.txt file and any crash logs that you see go by. In particular, if a plugin is having problems only on the Steam edition (but not the Global edition of 10.32r1) or if a plugin besides Gizmo crashes, I would like to see it!
UPDATE: We have determined that the crashes are caused by Steam introducing an ABI breakage of the libstdc++ runtime when we use one of their distribution tools. We are now working with an engineer at Valve software to solve this. In the meantime, the Steam distributed X-Plane has been rolled back to 10.31.
UPDATE 2015-01-21: Thanks to quick help from Valve software, we were able to re-release X-Plane 10.32r1 on Steam today which now gets along fine with plugins again.