Error running playground. Unable to find suitable target device. (iOS Swift)

Question

I created a new project in XCode.

File > New > Playground (option+shift+cmd+N)

Answer 1

Another possible way to encounter that issue is to get Xcode being auto-updated, while the simulator was launched.

The solution is like mentioned above but more polite:

1. Quit Xcode and Simulator app
2. Run in Terminal: killall -9 com.apple.CoreSimulator.CoreSimulatorService
3. Launch Xcode and find that all fixed now.

Sure, you can just reboot instead.