I have enabled debugging on /var/lib/dpkg/info/grub-pc.postinst when running dpkg --configure -a: https://termbin.com/7nh1
but I don't understand from the above output why it fails -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1891680 Title: grub-pc needs to detect when debconf points to invalid drive and stop in preinst, before unpacking files, and also treat this as a failure in postinst To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1891680/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs