Installing Ubuntu on Intel NUC: "the partition table format in use on your disks normally requires you to create a separate"

I'm trying to install Ubuntu on an Intel NUC, and I'm getting the following error message:

"The partition table format in use on your disks normally requires you to create a separate partition for boot loader code"

All the help online is for people who are trying to dual boot with Windows, but I am only trying to install Ubuntu. I used rufus to create an installation flash drive, but I'm trying to set it up to use my external hard drive as the main drive. (I would like to remove the flash drive after installation.)

The information I've found online all talks about UEFI vs legacy mode? But it never gives me any options wrt to UEFI. Also, the NUC doesn't enter the BIOS menus when I press F2 for some reason :(

What is the simplest way to install ubuntu on the NUC using my external hard drive? Is there a way to circumvent the flash drive and just use the hard drive to install?

1 Answer

When you boot the Ubuntu installer, it will boot in one of two modes, depending on how the boot medium was prepared and what your firmware settings are:

• EFI/UEFI mode -- This is the native mode on the vast majority of new computers. When booted in EFI mode, the Ubuntu installer normally likes to use the GUID Partition Table (GPT), on which it creates an EFI System Partition (ESP) to hold the EFI-mode boot loader. Your message indicates that this boot mode was not used in your attempt to install the OS.
• BIOS/CSM/legacy mode -- This mode is used on older (most pre-2011) computers, and is an option on most newer ones. When it boots in this mode, the Ubuntu installer will normally try to use the Master Boot Record (MBR) partition table; however, if the installation disk already uses GPT, the Ubuntu installer will want to see a BIOS Boot Partition on the disk to hold a BIOS-mode copy of GRUB. The message you're seeing indicates that you've got a GPT disk with no BIOS Boot Partition, and you've booted in BIOS/CSM/legacy mode.

There are a number of possible solutions to your problem:

• Switch to an EFI-mode boot -- Given no other information about your setup, this is the safest approach. You may need to re-create your installation disk to support EFI-mode booting, though, or change your firmware settings to ensure that the computer boots the installer in EFI mode. Rufus includes, IIRC, three options for boot modes and partition table types, so you can re-run it with the option to use GPT for (U)EFI-mode booting, then try again. Note, though, that if you pre-partitioned your target disk, you may need to tweak that configuration to include an ESP. Make it a FAT partition (I recommend 550 MiB in size) and mark it as an ESP by giving it a "boot flag" (in parted or GParted) or by giving it a type code of EF00 (in gdisk, cgdisk, or sgdisk).
• Create a BIOS Boot Partition -- If you're not booting any other OS, or if you're certain any other OS(es) on the disk are booting in BIOS mode, you can create a BIOS Boot Partition. This is normally a ~1 MiB partition that's identified by having the "bios_grub flag" set in parted or GParted or by having a type code of EF02 in gdisk or its relatives. Do not go this route if you've got another OS on the disk that's already booting in EFI mode and if you want to dual-boot with Ubuntu.
• Convert the disk to use MBR -- If the disk has no other OS(es) on it at all, then you can probably convert it to use MBR rather than GPT. You can do this destructively with parted or GParted by creating a new partition table. (These tools call MBR "msdos.") You can often convert non-destructively with gdisk, although there are caveats; see the gdisk documentation for details. When the disk is converted to MBR form, you can install using your current installation medium. This approach is likely to create huge new problems if you're already booting another OS from the disk. Also, this approach is likely impractical if the disk is over 2 TiB in size or if it uses 4096-byte logical sectors (as do many external disks and a few bleeding-edge internal disks).

If you need more help deciding what to do, please post more details about your current situation -- in particular, what (if any) other OS(es) you're booting from the disk, and what size and type of disk (internal/external, spinning disk/SSD) you're trying to use. Current partitioning details may also be helpful.