What is com.apple.CoreSimulator.CoreSimulatorService?
Quick answer
com.apple.CoreSimulator.CoreSimulatorService is the background service that runs and manages simulators for Xcode, the Simulator app and xcrun simctl. Seeing it in Activity Monitor is normal when you use simulators.
If it's using a lot of CPU or memory
- Shut down simulators you aren't using:
xcrun simctl shutdown all. - Quit Simulator and Xcode, then reopen.
- Remove simulators that can't run any more:
xcrun simctl delete unavailable.
Where its data lives
- Simulators:
~/Library/Developer/CoreSimulator/Devices - Runtimes:
/Library/Developer/CoreSimulator(disk images) - Logs:
~/Library/Logs/CoreSimulator
Questions
Can I force quit CoreSimulatorService?
It's better to shut down simulators and quit Simulator. Force quitting can leave simulators in a bad state until it restarts.
Why is it running when Simulator is closed?
Xcode and command-line tools like xcrun simctl use it too, not just the Simulator app.