package grub-efi-amd64-signed 1.66.14+2.02~beta2-36ubuntu3.14 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

I had a problem with Samba and winbind that I couldn't sort so tried to install a newer version alonside the existing. Got grub error.

I may have fixed it by going into recovery ode and selecting the grub fix option.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: grub-efi-amd64-signed 1.66.14+2.02~beta2-36ubuntu3.14
ProcVersionSignature: Ubuntu 4.10.0-42.46~16.04.1-generic 4.10.17
Uname: Linux 4.10.0-42-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
Date: Thu Dec 21 15:03:27 2017
Df:
 Filesystem 1K-blocks Used Available Use% Mounted on
 /dev/sda9 45544868 4687616 38520640 11% /
 /dev/sdb 1550400 1550400 0 100% /cdrom
 udev 1943984 0 1943984 0% /dev
 tmpfs 392008 11092 380916 3% /run
ErrorMessage: subprocess installed post-installation script returned error exit status 1
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.2
 apt 1.2.24
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.66.14+2.02~beta2-36ubuntu3.14 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)