http://paste.ubuntu.com/p/JVytDSVmGb/

[Rajesh]

grub2 error during 18.04 installation on 16.04

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubuntu-release-upgrader-core 1:18.04.21
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CasperVersion: 1.394
CrashDB: ubuntu
CurrentDesktop: ubuntu:GNOME
Date: Sat Aug 11 00:29:45 2018
LiveMediaBuild: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
PackageArchitecture: all
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=C.UTF-8
 SHELL=/bin/bash
SourcePackage: ubuntu-release-upgrader
Symptom: release-upgrade
UpgradeStatus: No upgrade log present (probably fresh install)