Xcode Cannot Run on the Selected Destination

Question

I was running my app this morning and now all of a sudden I am getting the following error when I try to run on the iPhone 5.1 simulator.

Cannot run on the selected

Answer 1

I restore the data from the time machine. Notice this is the exact same data that has been stored just 1 hour ago. The problem started yesterday. So it should be the EXACT same data.\

Yet it works.