"The workshop is experiencing problems right now. Steam advises that a power outage in the US server cluster has caused their database servers to shutdown. They have restored most services but there are still lingering issues. Any workshop/MOD/Skyrim Launcher issues you experience are related to this outage." From the steam creation kit group chat. Edit: It also says if you have problems with the launcher click play before it crashes. I've just been using skse myself.