After running sysprep to OOBE and generalize a master disk for cloning, at first run it prompted only for language/region and a machine name, then proceeded on to the CTRL+ALT+DELETE to login screen. It did not prompt for new administrator password.
The system had no local accounts except for the local administrator, which had been renamed. The administrator name and password used just before sysprep do not work.
How do I recover this? And why did it happen? Back up is old/stale, lose a lot of work if I can't get into this machine. Kicking myself for not backing up right before this procedure.