Can you please perform installation again, but this time launch a terminal and do:
ubuntu-bug ubiquity
Or alternatively please attach: /var/log/syslog /var/log/partman /var/log/installer/*
After reproducing your problem.
Can you please perform installation again, but this time launch a terminal and do:
ubuntu-bug ubiquity
Or alternatively please attach: installer/ *
/var/log/syslog
/var/log/partman
/var/log/
After reproducing your problem.