xcode instrument problem

i try to use intrument application from xcode to find out about some leaks in my app, i can use it when i running my ap开发者_StackOverflow中文版p on simulator, but the problem is, when i try to use instrument on running my app on device, it give me warning like this

target failed to run : remote exception encountered : 'Executable 'MyApp' ' is already running as process 97 which was lauched from the 'Xcode Debugger' process

is it something wrong?? i dont know what wrong step i made before, can somebody help me?? thank you

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this seems that your app is already running in your device and you are trying to run it again with instrument, try to close your app completely from device and then start it again with instrument.