This error interrupted my upgrade from 14.04 to 16.04.01
I hacked around it by manually editing /var/lib/dpkg/info/util-linux.postinst and removing all update-rc.d calls. All those were related to hwclock (I will probably reinstall hwclock at some time in the future to fix it up). As I understand, (new) update-rc.d is simply not suitable to be called at this moment of the upgrade.
This error interrupted my upgrade from 14.04 to 16.04.01
I hacked around it by manually editing /var/lib/ dpkg/info/ util-linux. postinst and removing all update-rc.d calls. All those were related to hwclock (I will probably reinstall hwclock at some time in the future to fix it up). As I understand, (new) update-rc.d is simply not suitable to be called at this moment of the upgrade.