Xcode 6.4 showing duplicate ‘Simulators’ with Unique Id

Solution from sunnyxx’s weibo:

1.quit Xcode and iOS Simulator

2.killall -9 com.apple.CoreSimulator.CoreSimulatorService

3.rm -rf ~/Library/Developer/CoreSimulator/Devices

4.reopen Xcode

Edit: sudo seems unnecessary to kill SimulatorService.This solution will remove all exist simulator and recreate all available version and type simulators.