error installing grub2 to disk

[Geoffrey Ford]

During Ubuntu installation, the installer informs me that there has been an error installing grub and that this is a fatal error.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.13
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.455
CurrentDesktop: ubuntu:GNOME
Date: Mon Jan 4 01:38:55 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
RebootRequiredPkgs:
 linux-image-5.8.0-25-generic
 linux-base
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)