In SDE geodatabase, unregistered the dataset, and attempted to build a network with two features: linear, simple edge, and point, simple junction. Allowed defaults throughout.
Result:
"Build Geometric Network failed.
"The object has been deleted and is no longer valid (referencing the BUILDERR table)
:File read/write error occurred.
"The operation was attempted on an empty geometry."
Exported the two layers to a file geodatabase and ran a Check Geometry from Toolbox.
Result: empty table for each layer.
Only help reference in ArcMap is use of the geo-network toolbar, but that requires the network to exist.
What next?