I'm on a Mac and I can't get 1.2 to work no matter what I do I did the update from the launcher for 1.1.3 and when the Squad synchronizer window starts after I've entered my account info it stops instantly saying that the "certificate verify failed". So I just went on to the KSP website and downloaded a fresh 1.2 launcher. The game starts but then gets stuck loading everything. I let it sit for a good few hours to no avail. It just says "loading asset bundle definitions". At least I got to see all the new, funny loading lines they added while I was intently waiting for the game to load.