It looks like grub tried to ask a question and debconf ran the gtk frontend and somehow dropped you to a subshell, which you typed exit from, then the gtk frontend errored out, causing the grub script to return the error.
** Package changed: grub2 (Ubuntu) => debconf (Ubuntu) -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to debconf in Ubuntu. https://bugs.launchpad.net/bugs/1786629 Title: package grub-efi-amd64 2.02-2ubuntu8.2 failed to install/upgrade: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1 Status in debconf package in Ubuntu: New Bug description: while upgrading to Ubantu 18.04 version pc hanged and it did not orked even after leaving for hours ProblemType: Package DistroRelease: Ubuntu 18.04 Package: grub-efi-amd64 2.02-2ubuntu8.2 ProcVersionSignature: Ubuntu 4.4.0-131.157-generic 4.4.134 Uname: Linux 4.4.0-131-generic x86_64 ApportVersion: 2.20.9-0ubuntu7.2 Architecture: amd64 Date: Sat Aug 11 22:33:39 2018 DistributionChannelDescriptor: # This is a distribution channel descriptor # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor canonical-oem-somerville-xenial-amd64-20160624-2 ErrorMessage: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1 InstallationDate: Installed on 2018-04-30 (103 days ago) InstallationMedia: Ubuntu 16.04 "Xenial" - Build amd64 LIVE Binary 20160624-10:47 ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.4.0-131-generic.efi.signed root=UUID=51e2afee-e9ee-4527-adf4-853e7c5827d5 ro acpi_rev_override quiet splash vt.handoff=7 Python3Details: /usr/bin/python3.6, Python 3.6.5, python3-minimal, 3.6.5-3ubuntu1 PythonDetails: /usr/bin/python2.7, Python 2.7.15rc1, python-minimal, 2.7.15~rc1-1 RelatedPackageVersions: dpkg 1.19.0.5ubuntu2 apt 1.6.3 SourcePackage: grub2 Title: package grub-efi-amd64 2.02-2ubuntu8.2 failed to install/upgrade: installed grub-efi-amd64 package post-installation script subprocess returned error exit status 1 UpgradeStatus: Upgraded to bionic on 2018-08-11 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/debconf/+bug/1786629/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
