package grub-efi-amd64-signed 1.34.13+2.02~beta2-9ubuntu1.11 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

I hope this helps. My desktop PC has 2 HDs. The 1st (primary) installed with 16.04 .The 2nd installed with 14.04.

Up until last week I was selecting 16.04 on boot up.and using the 2 HD as a backup

After an update I am unable to boot into 16.04

The follow dialogue appears along the top of the screen

/dev/sdb1:527762/60792832 files,9282817/243146240 Blocks

Now when I boot into 14.04, 16.04 loaded HD appears as an extension

ProblemType: Package
DistroRelease: Ubuntu 14.04
Package: grub-efi-amd64-signed 1.34.13+2.02~beta2-9ubuntu1.11
ProcVersionSignature: Ubuntu 3.13.0-88.135-generic 3.13.11-ckt39
Uname: Linux 3.13.0-88-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.21
Architecture: amd64
Date: Wed Jul 27 21:26:09 2016
DuplicateSignature: package:grub-efi-amd64-signed:1.34.13+2.02~beta2-9ubuntu1.11:subprocess installed post-installation script returned error exit status 1
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2014-12-31 (574 days ago)
InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2)
RelatedPackageVersions:
 dpkg 1.17.5ubuntu5.7
 apt 1.0.1ubuntu2.14
SourcePackage: grub2-signed
Title: package grub-efi-amd64-signed 1.34.13+2.02~beta2-9ubuntu1.11 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)