I open my project in Xcode 6.1. When I try to run the project, the button is grayed out. When I try to go to Product > Clean, the option is grayed out. When
I ran into another situation where this can occur. I work with a team we use Xcode server for continuous integration. The server wasn't seeing any simulators, but only for one project. I eventually determined that this was due to the fact that the version of Xcode on our server was one release earlier, and the Xcode project was set to build to the newest version available. Simply updating Xcode solved the issue for us.