I'm not quite sure when it started, but it was around the time iOS 7.0.3 came out, and it seems to be getting worse. Every 2-3 times I run my project on the device Xcode will record error: failed to launch '/private/var/mobile/Applications/1D114571-A4A6-4DF3-B5DE-8C7E6A627143/Client.app' -- failed to get the task for process -1, and the device will hang, showing the image of the launch. The home button and 4 fingers do nothing. The lock button will turn off the screen, but then you will not be able to turn it on. The strange thing is the work of Siri. The only way out of this state that I found is to hold the power and lock buttons until the device reboots. If I do not restart Xcode, it almost always happens in the next build. Perhaps restarting the computer does not help.
I tried reinstalling both Xcode and iTunes. I also performed "Delete all content and settings" on devices that are recovering from a backup and starting fresh.
Update
This is apparently a common problem in the Apple developer forums. This thread indicates that the problem is related to Xcode 5.0.1 and suggests using Xcode 5.0 for testing.
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