0

Before I begin, I know many questions here and on other sites are similar on some aspects, but I couldn't really fix my problem with what I've been reading over the last days.

I built a PC a couple years ago, and occasionally added new drives for storage, never having problems. Lately, I migrated my Windows 10 OS towards a new SSD, leaving me with 1TB HDD free. I thought it was the occasion for me to install Ubuntu on there.

Setting ub the install USB drive was easy, booting on it too. Then, things get less easy.

First of all, I don't have any option to "install Ubuntu alongside Windows". Whatever, I thought, and chose the custom partitioning option. There, I can see all my disks, and went to partition my HDD, /sdc, to install Ubuntu there. After creating a large ext4 partition with mount point "/", a swap larger than my RAM (not always necessary on newer PCs apparently, but who knows), a 36MB FAT32 partition as advised on ubuntu tutorials, and even a /boot partition, the first real problem I encounter is:

" No EFI System Partition was found. This system will likely not be able to boot successfully, and the installation process may fail. Please go back and add an EFI System Partition, or continue at your own risk."

I thought it was weird because it's not mentioned as necessary since Ubuntu is fine on Legacy/BIOS environments. Anyway I create an EFI partition in sdc, and start the installation, with boot point on /sdc (as I saw it was advised rather than sda where my other OS is located).

Everything runs fine until around the end, where I invariably get the "grub-install /dev/sdc failed fatal error". No matter what initial partitioning I go for (only ext4, ext4 + swap, ext4 + FAT32, etx4 + FAT32 + swap, adding /boot, /home etc), and no matter what boot mode I choose from my motherboard settings (UEFI or UEFI + Legacy), the installation wizard doesn't detect Windows, I am asked for that EFI partition, and it crashes the same way at the end.

I'm pretty sure I missed something around the MBR vs GPT formatting, or the boot mode, but I really can't figure out what.

Does anyone know where I'm going wrong? Thanks in advance :)

Improve this question
3
  • How the install media (full ISO version, not some mode specific version some tools can create) boots is how the install is made. Some machines allow you to set a mode preference (e.g. UEFI first over legacy) when both are present (like the install media). Be aware of launchpad bug 1396379, which puts the UEFI bootloaders onto sda regardless of what target location you specify. Was your Windows fully shut down (turn off the W10 power option that hibernates instead of shutting down.
    – ubfan1
    Sep 5, 2021 at 15:56
  • With multiple drives some suggest disconnecting or disable in UEFI all other drive. Several other work arounds in bug report. bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1396379 I mount correct ESP in middle of install, see #55. Or this: Remove esp flag from Windows before install to second or external drive - Tim Richardson askubuntu.com/questions/16988/…
    – oldfred
    Sep 5, 2021 at 20:10
  • I solved it in the end, first by unplugging all drives except the one for Linux, which I installed the standard way. Then, with grub still not detecting Windows, I figured I really needed to convert my win10 into GPT, which I did. And now everything's fine :)
    – Kaura Neden
    Sep 6, 2021 at 17:52

1 Answer 1

Reset to default
0

To successfully boot linux, you have to have the bootloader on a bootable disk. Typically, this is your first disk.

If you have an EFI system with an EFI partition on the primary disk, linux can install its bootloader in the same EFI partition that windows uses.

If you have a legacy system with a MBR format partition table on the primary disk, you have to have /boot on that primary disk so linux has somewhere to install its bootloader. This needs to be no smaller than 500M, 1G is probably better. If you make it too small, updates will fail.

If you have a legacy system with a GPT format partition table on the primary disk, you can create a BIOS partition for linux to install its bootloader. This can be pretty small (2-3M maybe?).

If you don't have room for these on your primary disk, you need to shave a bit off of one of your windows partitions to make room. It is safest to do this in windows disk manager.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .