I'm developing in Objective C with Xcode on a Mac exclusively to run on Mac and all of a sudden when I try to run I get the message: "a build only device cannot be used to run this target". If I go to the destination folder, the newly built app is there and runs from Finder, I just can't get it to run from within Xcode, which is inconvenient for testing. What setting am I missing or has changed? Up to now I could build and run with no problem.