package grub-efi-amd64-signed 1.93.3+2.02-2ubuntu8.2 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1

[Bob Luman]

I used Ubuntu 14.04 for several years. Then upgraded to 17. I upgraded to 18 and now I have problems with 17 starting every time I reboot. how can I kill 17 without losing my information? 17 also never connected to wi-fi but 18 and 14 had no problems. I don't know if this is a bug or not so just to let you know what I've seen.

ProblemType: Package
DistroRelease: Ubuntu 18.04
Package: grub-efi-amd64-signed 1.93.3+2.02-2ubuntu8.2
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
NonfreeKernelModules: kpatch_livepatch_Ubuntu_4_15_0_29_31_generic_41
ApportVersion: 2.20.9-0ubuntu7.2
AptOrdering:
 linux-signed-generic:amd64: Install
 NULL: ConfigurePending
Architecture: amd64
Date: Wed Aug 8 08:24:44 2018
DpkgHistoryLog:
 Start-Date: 2018-08-08 08:24:44
 Commandline: /usr/bin/unattended-upgrade
 Upgrade: linux-signed-generic:amd64 (4.15.0.29.31, 4.15.0.30.32)
ErrorMessage: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
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-signed
Title: package grub-efi-amd64-signed 1.93.3+2.02-2ubuntu8.2 failed to install/upgrade: installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)