Did an image of my C: with 2.72 GUI using same settings as before, it ran to completion ok, this time I received a dialog box to say it had completed. There was no mouse support, not even via mousepad, but return closed the box, x exited, return to reboot and system rebooted ok. It seemed to take longer to reboot, a later reboot done manually was back to nornal speed.
256g ssd drive with 107g in use, defrag run yesterday, an hour and half (no validation).