grub error every time I update or install a package

[chuse]

Since the last upgrade of Ubuntu I get an error message about grub, every time an update on any package is performed.

It actually doesn't change any functionality.

ProblemType: Package
DistroRelease: Ubuntu 13.10
Package: grub-pc 2.00-19ubuntu2.1
ProcVersionSignature: Ubuntu 3.11.0-13.20-generic 3.11.6
Uname: Linux 3.11.0-13-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.1
Architecture: amd64
Date: Tue Nov 19 03:28:10 2013
DuplicateSignature: package:grub-pc:2.00-19ubuntu2.1:subprocess installed post-installation script returned error exit status 20
ErrorMessage: subprocess installed post-installation script returned error exit status 20
InstallationDate: Installed on 2013-06-19 (152 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MarkForUpload: True
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.11.0-13-generic root=UUID=b1baa7fc-adca-4bab-9c70-e0b6dc910c0c ro quiet splash pcie_aspm=force
SourcePackage: grub2
Title: package grub-pc 2.00-19ubuntu2.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 20
UpgradeStatus: Upgraded to saucy on 2013-10-23 (26 days ago)

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]