Error: One or more of selected objects could not be deleted
When a geometric network and any or all of the feature classes participating in the network are selected and deleted within ArcCatalog, the result is the geometric network and orphan junction feature class are deleted, and this error occurs:
"One or more of selected objects could not be deleted"
After the error, none of the remaining feature classes can be deleted.
Solution or Workaround
Refresh the dataset by either using the F5 key, or by right-clicking the Feature Dataset and selecting the Refresh command. The remaining feature classes can then be deleted.