Storyboard broken after updating Xcode to version 10.3 (10G8) & app no longer is running

I just updated the Xcode to version 10.3 (10G8).

Now my project is not run with this error:

/* com.apple.actool.errors */
: error: Failed to find a suitable device for the type IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) with runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4
    Failure Reason: Failed to create new simulator device that matches IBSimDeviceTypeiPad2x (com.apple.dt.Xcode.IBSimDeviceType.iPad-2x) for runtime iOS 12.4 (12.4 - 16G73) - com.apple.CoreSimulator.SimRuntime.iOS-12-4 (Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4)
    Underlying Errors:
        Description: Invalid runtime: com.apple.CoreSimulator.SimRuntime.iOS-12-4
/* com.apple.actool.compilation-results */
/Users/xxx/Library/Developer/Xcode/DerivedData/xxxxx-dxlvvymxzdfqjubnuntqlxggtyja/Build/Intermediates.noindex/xxxxx.build/Debug-iphonesimulator/xxxxx.build/assetcatalog_generated_info.plist

And the storyboard is now like this:

I restarted my mac, the problem solved.

Running sudo killall -9 com.apple.CoreSimulator.CoreSimulatorService from terminal solved my problem.