grub install failed

[JCarsique]

during ubuntu 18.04 reinstall

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CasperVersion: 1.394
CurrentDesktop: ubuntu:GNOME
Date: Mon Jun 25 01:33:54 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
ProcEnviron:
 LANGUAGE=fr_FR.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=fr_FR.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[JCarsique (julien-carsique)]

Fixed following https://askubuntu.com/a/1032156/40949
cd /boot/efi/EFI
mv ubuntu ubuntu-old
apt install -f
mv ubuntu-old ubuntu
update-grub2

[Phillip Susi (psusi)]

Your disk is currently partitioned to boot in bios mode, but you booted the installer in EFI mode. You either need to boot the installer in bios mode, 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.