When you want to run the app to test in simulator/device you press the CMD+R (or press the Run button), this then complies the project and launches the app on the simulator/device. If the any other app is running on simulator/device this command terminates that instance of that app and then re-deploys/run the app associated to you project. Rarely you can encounter an error where in XCode is not able to deploy/run on every CMD+R but does it on every second time. This is annoying and leds to productivity loss.
This happens if somehow you two copies of the -Info.plist file in your project. You could have accidentally added the second one from another project or created by hand and not deleted the first one etc. Check your project for that and delete the one that is duplicate or not required. This should solve this issue.<!>