package shim-signed 1.32+0.9+1474479173.6c180c6-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[TPack]

Received report immediately after upgrade from 17.04 to 17.10.

ProblemType: Package
DistroRelease: Ubuntu 17.10
Package: shim-signed 1.32+0.9+1474479173.6c180c6-1ubuntu1
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
.proc.sys.kernel.moksbstate_disabled: Error: [Errno 2] No such file or directory: '/proc/sys/kernel/moksbstate_disabled'
ApportVersion: 2.20.7-0ubuntu3
Architecture: amd64
Date: Fri Oct 20 10:09:18 2017
EFITables:
 Oct 20 10:30:57 tom-MS-7913 kernel: efi: EFI v2.31 by American Megatrends
 Oct 20 10:30:57 tom-MS-7913 kernel: efi: ESRT=0x7e1fac98 ACPI=0x7d20c000 ACPI 2.0=0x7d20c000 SMBIOS=0x7e1faa98
 Oct 20 10:30:57 tom-MS-7913 kernel: esrt: Reserving ESRT space from 0x000000007e1fac98 to 0x000000007e1facd0.
 Oct 20 10:30:57 tom-MS-7913 kernel: Secure boot could not be determined
ErrorMessage: subprocess installed post-installation script returned error exit status 1
GrubDiff: Binary files /boot/efi/EFI/ubuntu/grubx64.efi and /usr/lib/grub/x86_64-efi-signed/grubx64.efi.signed differ
InstallationDate: Installed on 2016-04-28 (539 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
Python3Details: /usr/bin/python3.6, Python 3.6.3, python3-minimal, 3.6.3-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.14, python-minimal, 2.7.14-2ubuntu1
RelatedPackageVersions:
 dpkg 1.18.24ubuntu1
 apt 1.5
SecureBoot: 6 0 0 0 0
SourcePackage: shim-signed
Title: package shim-signed 1.32+0.9+1474479173.6c180c6-1ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to artful on 2017-10-20 (0 days ago)

[Steve Langasek (vorlon)]

Why is /boot/efi not mounted on your system? Please attach your /etc/fstab.

[TPack (e-contact-packlaw-net)]

I think /boot/efi is mounted on my system as shown by lsblk so I'm not sure why I got this error.

$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 931.5G 0 disk
├─sda1 8:1 0 128M 0 part
├─sda2 8:2 0 1000M 0 part
├─sda3 8:3 0 260M 0 part /boot/efi
├─sda4 8:4 0 500M 0 part
├─sda5 8:5 0 418.4G 0 part /media/tom/Windows8_OS
├─sda6 8:6 0 2G 0 part [SWAP]
└─sda7 8:7 0 296.1G 0 part /
sdd 8:48 1 3.7G 0 disk
└─sdd1 8:49 1 3.7G 0 part

[Steve Langasek (vorlon)]

The bug contents clearly show that at the time the bug report was filed, /boot/efi was mounted. But equally clearly, the bug report shows that the grub package could not find the EFI directory at package upgrade time:

Installing for x86_64-efi platform.
grub-install: error: cannot find EFI directory.
Failed: grub-install --target=x86_64-efi --no-extra-removable
WARNING: Bootloader is not properly installed, system may not be bootable

Can you please attach /etc/fstab still?

[TPack (e-contact-packlaw-net)]

Attaching sanitized etc/fstab

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Steve Langasek (vorlon)]

More recent versions of grub will attempt to mount /boot/efi dynamically for you if not already mounted; considering this resolved at this point.