[SOLVED] Xcode 4.4: another instance of this process was already running or is hung in the debugger

I have seen this similar question on SO in a few places but all of them are related to Simulator and old Xcode version. For examples, Error: unknown error code. this process was already running or is hung in the debugger and Error when testing on iOS simulator: Couldn't register with the bootstrap server

I have never seen this error before until I upgraded my Xcode to 4.4. It works fine on the simulator but not on an iPhone. I have also upgraded Xcode to 4.4.1 today but no luck. How to get rid of this error on an iPhone?

Couldn't register com.mycompany.myapp with the bootstrap server. Error: unknown error code.
This generally means that another instance of this process was already running or is hung in the debugger.