Now you should be able to run the Playground successfully, cheers! 🍻 I also suggest switching to manually run instead of automatic run in the playground to reduce the CPU usage.

Then in the right pane of the Playground window, select ' macOS' in Playground Settings -> Platform. The solution for this is to switch to macOS platform in the Playground, let the playground code run in your macOS environment directly instead of spinning up an iOS simulator process to run it.įirst, ensure your Playground doesn't use any UIKit function (eg: UIView etc), and remove the top import UIKit line if it is there.

That's the reason why you keep stuck on 'Launching Simulator' or 'Running.' even after restarting Xcode. It will get stuck after the error and remain stuck until you kill this process. Somehow the CoreSimulator process become unstable after an error got raised in the Playground. To run it on iOS platform, the Playground will spin up an iOS Simulator in the background.Īnd it is this iOS Simulator thing that causes the stuck issues! Restarting Xcode doesn't work because the simulator process doesn't get restarted when you restart Xcode as it is a separate process. When you create a Playground in Xcode, it will use iOS platform to run the code by default. Then I noticed it stuck on 'Launching Simulator' and thought it might have something to do with the iOS Simulator since restarting Xcode doesn't help 🤔. I tried restarting Xcode, Mac to no avail and almost attempt to reinstall Xcode. Then I quit Xcode and open the Playground again, and the same issue persist 😭. I ran into this issue last week while trying out NSPredicate examples in Playground, it happened after an error during execution of code.Īfter the error appeared, no big deal, I changed the code and run it again, then the Playground got stuck in Running. Apple recommends beginner to use Playground and yet Playground is full of issues like this 🤦‍♂️. Ever stuck in ' Launching Simulator' or ' Running Playground' when you fire up Playground to write some code? Despite restarting Xcode or even Mac multiple times, the problem still persists? I have seen many beginners give up on learning Swift because of this issue and this really sadden me, Apple should do better on this.

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