No, everything is working now. Before I open any project that uses the playground, I edit the podfile and include the extra lines that are given towards the end of the answers to this question: Playground does not execute on first chapter - #28 by hhschulz
After that, I run ‘pod install’ and ‘pod update’ (and then run them both a second time). After that, the project usually run OK. The playground still stops from time to time, particularly if it tries to run the code while you are typing it in. When that happens, I stop and start Xcode and that usually fixes things.
I think Xcode playgrounds are still much too fragile to use in tutorials.
Thanks,
Vince.