When I try those commands I get error messages (see below).

I just remembered something that might be related to this bug. A few
months ago I followed a guide to fix a boot error (the computer would
not boot into ubuntu without live DVD). I was able to fix the boot
problem, but maybe its solution is causing this bug? Here is the guide
I followed: http://heeris.id.au/2014/ubuntu-plus-mac-pure-efi-boot/#fixing-efi

cristina@asuka:~$ sudo apt install strace
[sudo] password for cristina:
Reading package lists... Done
Building dependency tree
Reading state information... Done
strace is already the newest version (4.11-1ubuntu3).
The following packages were automatically installed and are no longer required:
  linux-headers-4.4.0-81 linux-headers-4.4.0-81-generic
  linux-image-4.4.0-81-generic linux-image-extra-4.4.0-81-generic
  linux-signed-image-4.4.0-81-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
Setting up grub-efi-amd64-signed (1.66.12+2.02~beta2-36ubuntu3.12) ...
Installing for x86_64-efi platform.
grub-install: error: Can't create file: No such file or directory.
dpkg: error processing package grub-efi-amd64-signed (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up shim-signed (1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1) ...
Installing for x86_64-efi platform.
grub-install: error: Can't create file: No such file or directory.
dpkg: error processing package shim-signed (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 grub-efi-amd64-signed
 shim-signed
E: Sub-process /usr/bin/dpkg returned an error code (1)
cristina@asuka:~$ sudo strace -ff -o /tmp/grub-install-trace -s 256
grub-install --target=x86_64-efi
Installing for x86_64-efi platform.
grub-install: error: Can't create file: No such file or directory.
cristina@asuka:~$


On 8/1/17, Steve Langasek <email address hidden> wrote:
> Ok, there's nothing obviously wrong in that output.  Can you please try
> the following commands:
>
>  sudo apt install strace
>  sudo strace -ff -o /tmp/grub-install-trace -s 256 grub-install
> --target=x86_64-efi
>
> And attach the resulting /tmp/grub-install-trace* files to this bug
> report?
>
> ** Package changed: shim-signed (Ubuntu) => grub2 (Ubuntu)
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1707832
>
> Title:
>   package shim-signed 1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1
>   failed to install/upgrade: subprocess installed post-installation
>   script returned error exit status 1
>
> Status in grub2 package in Ubuntu:
>   Incomplete
>
> Bug description:
>   I tried to update ubuntu and I got this error message. I am using
>   MacBook late 2007 with lubuntu 16.04 LTS 64bit.
>
>   ProblemType: Package
>   DistroRelease: Ubuntu 16.04
>   Package: shim-signed 1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1
>   ProcVersionSignature: Ubuntu 4.4.0-87.110-generic 4.4.73
>   Uname: Linux 4.4.0-87-generic x86_64
>   .proc.sys.kernel.moksbstate_disabled: 0
>   ApportVersion: 2.20.1-0ubuntu2.10
>   Architecture: amd64
>   BootEFIContents:
>    fw
>    fwupx64.efi
>    System
>   Date: Mon Jul 31 17:22:53 2017
>   EFIBootMgr:
>    BootCurrent: 0000
>    Timeout: 0 seconds
>    BootOrder: 0004
>    Boot0004* Ubuntu 16.04.2
> LTS	HD(1,GPT,6aa06c3c-cd2f-477e-a7a8-01871ef8de84,0x800,0x100000)/File(\System\Library\CoreServices)
>    BootFFFF*
> 	PciRoot(0x0)/Pci(0x1f,0x2)/Sata(0,0,0)/HD(1,GPT,6aa06c3c-cd2f-477e-a7a8-01871ef8de84,0x800,0x100000)/File(\EFI\Ubuntu
> 16.04.2 LTS\System\Library\CoreServices\boot.efi)
>   EFITables:
>    Jul 31 08:51:10 asuka kernel: efi: EFI v1.10 by Apple
>    Jul 31 08:51:10 asuka kernel: efi:  ACPI=0xbeeee000  ACPI 2.0=0xbeeee014
> SMBIOS=0xbeec3000
>   ErrorMessage: subprocess installed post-installation script returned error
> exit status 1
>   InstallationDate: Installed on 2017-05-10 (82 days ago)
>   InstallationMedia: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64
> (20150218.1)
>   RelatedPackageVersions:
>    dpkg 1.18.4ubuntu1.2
>    apt  1.2.20
>   SourcePackage: shim-signed
>   Title: package shim-signed 1.32~16.04.1+0.9+1474479173.6c180c6-1ubuntu1
> failed to install/upgrade: subprocess installed post-installation script
> returned error exit status 1
>   UpgradeStatus: No upgrade log present (probably fresh install)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1707832/+subscriptions
>