Device Will not run error iOS 9 Xcode 7.0

The explanation of issue and fix: - XCode 7 started to monitor connections from applications to the device - If XCode "does not like" the application or type activity between computer and iOS device - it displays such weird message

Fix - exit all applications that might communicate with iOS device: - AppCode - most probably it is causing issues - XCode instrumentation - usually not causing issues but sometimes might do - iTunes - never seen but it's also probable target

Just to have no side-effects it's better to have device rebooted (with cable detached) and make project Clean prior next attempt to run on a device.

Hope that will save you few minutes and some neurons in your brain

Xcode store information about different iOS devices that were connected to your computer in /Users/"your home directory"/Library/Developer/Xcode/iOS DeviceSupport. (OS X El Capitan, Xcode 6.4). I found directory inside it that had the same name as iOS version of iPhone that had such kind of error and delete. When I connected my iPhone one more time, Xcode started to copy necessary symbols. After Xcode finished, I have not receive error again. I suppose other Xcode versions (7.3.1, 8.0) store information about iOS Devices in same directory.

Well, it's worth trying to do as the error message proposes: reboot and reconnect the device.

UPDATE: it is possible, that two reboots are required. Take a look at comments to this answer.

UPDATE 2: If nothing else helps, try restoring the device.

Had the same problem now. I had Instruments open. When I closed it, Xcode would allow my iPhone. Might be worth a shot.