Public bug reported: It seems to have started happening after denying from a script to disable safe booting. The reason why I did this was that nvidia drivers malfunctioned otherwise. I do not know if this is the real cause, but I observed it after this action. Also, in conjuction with this bug, I have observed high cpu usage from apport, before the above error appearing on the screen.
ProblemType: Package DistroRelease: Ubuntu 16.04 Package: grub-efi-amd64 2.02~beta2-36ubuntu3.11 ProcVersionSignature: Ubuntu 4.4.0-79.100-generic 4.4.67 Uname: Linux 4.4.0-79-generic x86_64 NonfreeKernelModules: nvidia_uvm nvidia_drm nvidia_modeset nvidia ApportVersion: 2.20.1-0ubuntu2.6 AptOrdering: grub-efi-amd64: Configure grub-efi-amd64-signed: Configure NULL: ConfigurePending Architecture: amd64 Date: Sun May 21 02:24:24 2017 DpkgTerminalLog: Setting up grub-efi-amd64 (2.02~beta2-36ubuntu3.10) ... /var/lib/dpkg/info/grub-efi-amd64.postinst: line 703: syntax error near unexpected token `fi' dpkg: error processing package grub-efi-amd64 (--configure): subprocess installed post-installation script returned error exit status 2 DuplicateSignature: package:grub-efi-amd64:2.02~beta2-36ubuntu3.11 Setting up grub-efi-amd64 (2.02~beta2-36ubuntu3.10) ... /var/lib/dpkg/info/grub-efi-amd64.postinst: line 703: syntax error near unexpected token `fi' dpkg: error processing package grub-efi-amd64 (--configure): subprocess installed post-installation script returned error exit status 2 ErrorMessage: subprocess installed post-installation script returned error exit status 2 InstallationDate: Installed on 2016-06-06 (353 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) ProcCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-79-generic root=UUID=251db89b-1194-496c-addb-746959682b8f ro quiet splash pcie_aspm=force acpi_osi= vt.handoff=7 RelatedPackageVersions: dpkg 1.18.4ubuntu1.2 apt 1.2.20 SourcePackage: grub2 Title: package grub-efi-amd64 2.02~beta2-36ubuntu3.11 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2 UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: grub2 (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-package package-from-proposed xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1693783 Title: package grub-efi-amd64 2.02~beta2-36ubuntu3.11 failed to install/upgrade: subprocess installed post-installation script returned error exit status 2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1693783/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs