I believe the error here is that the install_device was invalid. Instead of '(sdb3)', it should have been '(hd1)' or /dev/sdb.
Oct 29 22:21:55 ubuntu grub-installer: info: Installing grub on '(sdb3)' Oct 29 22:21:55 ubuntu grub-installer: info: grub-install supports --no-floppy Oct 29 22:21:55 ubuntu grub-installer: info: Running chroot /target /sbin/grub-install --no-floppy "(sdb3)" Oct 29 22:21:56 ubuntu grub-installer: Probing devices to guess BIOS drives. This may take a long time. Oct 29 22:21:56 ubuntu grub-installer: Format of install_device not recognized. ** This bug is no longer a duplicate of bug 73825 Xubuntu installer ** Tags added: invaliddevice ** Tags added: grub -- Installer crashed while installing grub to sdb3 https://launchpad.net/bugs/69159 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
