Grub failed to write to disk as I was attempting a dual boot with Win10

[Richard Wilson]

efi partition was sdb2

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.17
ProcVersionSignature: Ubuntu 5.11.0-27.29~20.04.1-generic 5.11.22
Uname: Linux 5.11.0-27-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.18
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445.1
CurrentDesktop: ubuntu:GNOME
Date: Sat Nov 20 14:32:45 2021
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 20.04.3 LTS "Focal Fossa" - Release amd64 (20210819)
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)