unable to install GRUB during Ubuntu install

[Íñigo]

The PC is a dual system, Ubuntu 22.04 and Win10.
In an Ubuntu update, Ubuntu was damaged, so I did a reinstall.
I chose "something else" during the install, and chose the bootloader to install in sdc4 and root (/) in sdc6, formatting sdc6. This would be to install identically as before.
However, the system was unable to install GRUB in sdc4,stopped the installation and indicated the error.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: ubiquity 22.04.17
ProcVersionSignature: Ubuntu 5.15.0-43.46-generic 5.15.39
Uname: Linux 5.15.0-43-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.470
Date: Sun Oct 30 09:59:06 2022
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 22.04.1 LTS "Jammy Jellyfish" - Release amd64 (20220809.1)
RebootRequiredPkgs: Error: path contained symlinks.
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)