installer crashed, grub not installed

[Michael Dooley]

Repeat failure of a few days ago. Installing ubuntu-mate 20.10 groovy on Dell laptop. Grub not able to install on /dev/sda, subsequent crash of installer.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: ubiquity 20.10.8
ProcVersionSignature: Ubuntu 5.4.0-26.30-generic 5.4.30
Uname: Linux 5.4.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu42
Architecture: amd64
CasperMD5CheckMismatches: ./pool/restricted/n/nvidia-graphics-drivers-390/libnvidia-decode-390_390.138-0ubuntu2_i386.deb
CasperMD5CheckResult: skip
CasperVersion: 1.452
Date: Tue Jul 21 14:03:09 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu-mate.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu-MATE 20.10 "Groovy Gorilla" - Alpha amd64 (20200721)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)