Just a passing update - Next day normal boot hangs - blank screen. However powering off, choosing advanced options on grub boot menu and then activating ubuntu recovery mode, followed by resume normal startup works around the hang, and I am back to lightdm desktop login OK.
Just a passing update - Next day normal boot hangs - blank screen. However powering off, choosing advanced options on grub boot menu and then activating ubuntu recovery mode, followed by resume normal startup works around the hang, and I am back to lightdm desktop login OK.