I had a similar problem. Pressing Alt+F4 to switch to the installer output, I could see
Attempting to install GRUB to a partitionless disk or to a partition. This is a BAD idea.
It would appear that my USB disk was detected as
/dev/sda, and my target hard disk was detected as
/dev/sdb, based on the output from
So I fixed it by activating a shell in the Alt+F2 session and ran the following:
chroot /target grub-install /dev/sdb
Then I switched back to the installer (Alt+F1) and hit "Continue without bootloader".
Once installation had finished (I unplugged the USB stick), I was presented with a
grub> prompt, so I followed the instructions here, as follows (this assumes that your boot disk is
(hd0) (hd0,msdos5) (hd0,msdos1)
grub> set root=(hd0,msdos1)
grub> ls /
lost+found/ etc/ ...
grub> ls /boot
grub> linux /boot/vmlinuz- # press Tab
# then add the following
grub> initrd /boot/initrd # press Tab
Once the system is booted, log in and then:
sudo grub-install /dev/sda
Reboot to check it's working:
sudo shutdown -r now