Problem: Network dataset is empty after it is copied from one geodatabase to another
After copying a network dataset from one geodatabase to another, previewing the copied network dataset in ArcCatalog shows an empty display. The original network dataset, however, shows its network elements when previewed in ArcCatalog.
When a network dataset is copied from one geodatabase to another, only the schema information of the network dataset is copied. The network elements are not copied.
Solution or Workaround
In ArcCatalog, right-click the copied network dataset and click Build. This will create the network elements in the copied network dataset.