Quote - SM:"This has been discovered to be an issue with the Cache in the new Library on MACs that prevents the some items from displaying when a Runtime has a large number of folders and will be fixed in the Service Release."

SM inform me that they working on the problem over the weekend, and a Service Release is imminent.

In the meantime using the search option remains the only way to use external runtime content if you have missing items.

Good to see that they're listening and doing something about it, a very positive sign from SM.