Grub failed to install because your computer booted the installer in bios mode, and /dev/sda is partitioned with GPT and appears to be configured to boot in UEFI mode. If your computer normally boots in UEFI mode, then you need to have it boot the installer in UEFI mode, rather than bios mode. If it is supposed to boot in bios mode, then you need to create a 1 mb bios_grub boot partition in order to install grub to a GPT disk.
** Changed in: grub-installer (Ubuntu) Status: New => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1361333 Title: new duo windows 8.1 and ubuntu install 14.04.1 grub could not be installed. 'critical faillure' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1361333/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs