package grub-efi-amd64-signed (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Mahesh Kamble]

Not able to dule boot my windows 7.
http://past.ubuntu.com/25811665/
http://past.ubuntu.com/25811463/
http://past.ubuntu.com/25802632/

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: grub-efi-amd64-signed (not installed)
ProcVersionSignature: Ubuntu 4.13.0-16.19-generic 4.13.4
Uname: Linux 4.13.0-16-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.5
AptOrdering:
 grub-efi-amd64-signed: Configure
 shim-signed: Configure
 NULL: ConfigurePending
Architecture: amd64
Date: Tue Oct 24 23:49:35 2017
Df:
 Filesystem 1K-blocks Used Available Use% Mounted on
 /dev/sda6 50847092 4024232 44216928 9% /
 udev 1929140 0 1929140 0% /dev
 tmpfs 388948 6364 382584 2% /run
DpkgTerminalLog:
 Setting up grub-efi-amd64-signed (1.66.7+2.02~beta2-36ubuntu3.7) ...
 Installing for x86_64-efi platform.
 grub-install: error: cannot find EFI directory.
 dpkg: error processing package grub-efi-amd64-signed (--configure):
  subprocess installed post-installation script returned error exit status 1
DuplicateSignature:
 package:grub-efi-amd64-signed:(not installed)
 Installing for x86_64-efi platform.
 grub-install: error: cannot find EFI directory.
 dpkg: error processing package grub-efi-amd64-signed (--configure):
  subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.19
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed (not installed) failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Brian Murray (brian-murray)]

Due to a bug in apport's method for creating a duplicate signature, the DuplicateSignature in this report was incorrect. We are fixing that now, sorry for the noise!