Grub2 failed to install

[Suresh Nimbalkar]

I was upgrading from 16.04 to 18.04. The main reason for upgrade is constant problems with WI-FI in 16.04.

I have a UEFI system, hence, in my view, GRUB is not required. However, Ubuntu installs GRUB by default. I had the GRUB installed from 16.04. I had tried removing the GRUB using CMD commands before trying to install 18.04. However, when I rebooted the system, GRUB greeted me to 16.04.

I started 18.04 installation as an upgrade to 16.04. The installer failed to install GRUB.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.4 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.15.0-13.14-generic 4.15.10
Uname: Linux 4.15.0-13-generic x86_64
ApportVersion: 2.20.9-0ubuntu2
Architecture: amd64
CasperVersion: 1.392
CurrentDesktop: ubuntu:GNOME
Date: Fri Apr 6 13:29:03 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180403)
ProcEnviron:
 LANGUAGE=en_IN
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
 LC_NUMERIC=C.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Phillip Susi (psusi)]

Your disk is currently partitioned to boot in bios mode, but you booted the installer in EFI mode. A warning message prompted you that this could be a problem and recommended performing a bios mode install instead, but you chose not to. You either need to perform the bios mode install, or partition the disk using GPT and set up an EFI system partition to install in EFI mode. This will be done for you if you choose the "use entire disk" guided install option.