Thanks to Moreno and Igor for the Event Viewer suggestions.
Here are a few lines of log file where they differ between a
good install and a bad incomplete install. The good install was
from my Shop PC with Windows 10 Pro.
BTW, I had success with another Dell PC with Win 10 Pro about 4
months ago. This problem appears to be a one-off.
Good Install:
Called AclCheck(C:\Program Files\PostgreSQL\9.6\data)
Called IsVistaOrNewer()...
'winmgmts' object initialized...
Version:10.
MajorVersion:10
Executing icacls to ensure the SHOP-PC\Dale account can
read the path C:\Program Files\PostgreSQL\9.6\data
Executing batch file 'rad0510A.bat'...
processed file: C:\Program Files\PostgreSQL\9.6\data
Successfully processed 1 files; Failed processing 0 files
Bad Install:
Called AclCheck(D:\PostgreSQL\9.6\data)
Called IsVistaOrNewer()...
'winmgmts' object initialized...
Version:10.
MajorVersion:10
Executing icacls to ensure the WINDOWS-6BEGVO1\don king
account can read the path D:\PostgreSQL\9.6\data
Executing batch file 'rad6DBC7.bat'...