I've checked Apttermlog.txt more carefully, and it seems to be caused by a circular dependency:
systemd-sysv < systemd < libcryptsetup4 < libdevmapper1.02.1:amd64 < dmsetup < libdevmapper1.02.1 -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to init-system-helpers in Ubuntu. https://bugs.launchpad.net/bugs/1509816 Title: Upgrade from 14.04 to 15.04 missed systemd-sysv and init package init 1.22ubuntu11 failed to install/upgrade: pre-dependency problem - not installing init To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/init-system-helpers/+bug/1509816/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
