I have used Ubuntu for many years and someone gave me a computer with Windows 8, later updated to 8.1 and, finally, to 10. The thing is I want to install Ubuntu LTS (14.04.3) alongside Windows 10 (dual boot), and because of my personal circumstances I need to use the "custom installation" feature. UEFI boot, guid/gpt partition table. The ubuntu live pendrive is booted in UEFI mode.
When I started the custom installation it asked me where to install grub. I selected the whole disk (dev/sda) and continued. When it finished and rebooted, it booted into Windows 10, and Windows 10 doesn't recognize any other OSes. It's because of the UEFI partition, with only Windows boot manager installed.
So what do I need to do in order to install grub in the UEFI partition without deleting Windows Boot Manager? Do I just have to select "Install GRUB in dev/sda2 (UEFI partition)"? Will it keep Windows Boot Manager, as said in the UEFI wiki article? (I have read many post and the uefi article but none of them say what to do in my case.)
Quotes from the wiki:
"If your disk already contains an ESP (eg if your computer had Windows 8 preinstalled), it can be used for Ubuntu too. Do not format it."
"Note that in a UEFI-mode installation, Ubuntu will not ask you where to install the boot loader. If it does, or if it complains about the lack of a BIOS Boot Partition, you've probably accidentally booted in BIOS/CSM/legacy mode."

  • From live installer does this show an ubuntu entry in UEFI? sudo efibootmgr -v? You have to boot in UEFI mode and may have to add efibootmgr with sudo apt-get install efibootmgr What brand/model system. Installing to sda is correct and with UEFI it knows to put boot files into the ESP - efi system partition. – oldfred Aug 26 '15 at 20:52
  • It's an HP ENVY m6-1103es. So should I select sda and not the efi partition? When using that command I read this. (Unidad de disco duro USB=USB hard drive unit) – Martín Gómez Aug 28 '15 at 12:10
  • HP's only boot Windows with default settings, you need one of the work arounds that have been found. Most copy grub or shim to bootx64.efi and boot a hard drive entry. Some like rEFInd: askubuntu.com/questions/486752/… and: askubuntu.com/questions/244261/… – oldfred Aug 28 '15 at 15:08

Ubuntu 14.04.3 LTS with Windows 10 UEFI GUID custom installation

Details of the system in which I have successfully installed Ubuntu 14.04 LTS:

  • DELL Inspiron 11 (2-IN-1, 3158)
  • Processor - Intel core i3 - 6100U
  • RAM - 4.00 GB
  • UEFI secure boot enabled
  • HDD - 500GB GUID
  • Pre-installed OS - Windows 10 Home Single Language

Steps to install Ubuntu 14.04 LTS alongside Windows 10 and without overwriting Windows Boot Manager:


  • 50GB un-allocated HDD space
  • Bootable USB of Ubuntu 14.04 (64bit)
  • Disable "Turn on fast startup" in Windows 10

Installation Procedure

  • Boot system with Ubuntu 14.04 USB in 'UEFI secure boot enabled' mode.

  • Select Live session.

  • Double click 'Install Ubuntu' icon on desktop to begin installation.

  • Installer will auto-detect the presence of Windows boot manager and present applicable options for Installation type.

  • Under Installation Type, select "Something else" and continue.

  • Next screen will show the current partitions available on the HDD. Select the un-allocated space and create partitions as described in next steps.

  • UEFI partition : 250MB

  • Boot partition : 250MB

  • Root partition : 48GB

  • Swap: remaining space

  • Important step: To install boot loader: Select the UEFI partition which was created in above steps. Do not select the existing UEFI partition which is used by Windows 10.

  • Continue to begin the installation.

Once installation is over, reboot the system. You will see GRUB loaded with the options to boot Ubuntu or Windows 10.

At this step, you can verify that both the OSes are working fine.

Now, reboot the system again and enter into the UEFI settings by pressing appropriate button during boot-up (in my case it is F2).

You will observe that there are multiple options in the UEFI boot menu.

  • Ubuntu
  • Windows 10
  • And one or two more entries

Now make Windows 10 as the first option for booting.

Save the settings and exit UEFI setup.

You'll observe that now Windows 10 is booting directly without giving any selection option for Ubuntu. Since, we have not used the Windows 10 UEFI partition, so windows boot manager is intact.

Now, in order to boot Ubuntu, press F12 (in other laptop models it may be different) during system startup to see the UEFI boot menu. Select Ubuntu to boot.

  • Note: ST Microelectronics 3-axis digital accelerometer was not detected by Ubuntu 14.04, so automatic changeover to portrait mode will not work in table mode.
  • Welcome to Ask Ubuntu! Nice first answer :D – cat Apr 11 '16 at 1:00

There are few things to be considered, may be these can help you.

-As of my experience UEFI installation does not ask whether to install grub, it is automatically installed on your EFI partition.

-In order to check if your ubuntu installation has completed properly you can boot ubuntu live, mount the EFI partition and check whether grub is present there.

-If grub is present then goto UEFI boot menu and check if ubuntu is selected instead of Windows Boot Manager in the 1st boot order.

-Last but not the least, rather than installing alongside windows i would prefer you to create two separate partition for the ubuntu installation viz. swap (nearly size of your RAM) and ext4 (for your ubuntu installation with your desired size) and during the installation choose manual option and use that created partition for ubuntu installation. You can create new partition by shrinking your existing partition from windows in disk management tool without loosing your data or you can also use gparted from live ubuntu.

  • -I don't know how to check if grub is in UEFI. How do you mount it? <br> -I used the "Something else" feature and I had already created the swap partition. Maybe that's why it's asking me where to install the boot manager. <br> -In my UEFI settings I can only tell the computer to boot from the UEFI partition, I can't choose between Windows Boot Manager and Ubuntu. <br> Thanks for your help! – Martín Gómez Aug 28 '15 at 11:33

My toshiba (EFI/GPT) started with pre-installed w8.1, and using a usb stick (unetbootin), I simply shrank w8 into a 40 GB 'broom closet' and then installed Mint (Ubuntu).
I then had to use boot-repair-disk (see below) to stop windoze always behaving like it was the only kid on the block.

The usb was prepared using unetbootin in w8.1 and thus probably automatically booted in uefi mode, and installed its boot loader directory (and grub/loader) therein.

If you can log into your Ubuntu installation, open a terminal and

cd /boot

ls -al

look for a directory called efi (if it isn't there, your ubuntu isn't a uefi installation) If efi is there,

cd ./efi

ls -al

and you'll probably see yet another set of directories, including one called EFI so

cd ./EFI and look for a directory called ubuntu If it's there, your ubuntu is pretty definitely installed under uefi, and all you need is to download a copy of boot-repair-disk (google it) prepare a bootable usb via unetbootin in windoze - boot it and follow instructions. (boot-repair may already be on your ubuntu install pendrive)

If you haven't actually finished installing Ubuntu, go back into windoze, google unetbootin and install it, re-prepare your pendrive with your ubuntu iso using unetbootin in windoze, shut windoze down and boot into the pendrive, use gparted to shrink windoze main partition create ext4 partition and swap and 'manually' install ubuntu in the ext4 one. Then reboot.

You may find yourself only offered windoze, and if so, download boot-repair-disk, re-do your pendrive using unetbootin and your boot-repair-disk iso. reboot into that, and follow the default instriuctions.

Everything should be ticketty boo.

Hope that's some help ;)

  • I've installed Ubuntu (with the swap partition) and the installer said: "Ubuntu is installed, reboot" I rebooted and found Windows, so I would need more info about how to do what you say in the last paragraph, and then I guess it boot into Ubuntu with no problem. Can you tell me more about what to do with boot-repair-disk? (I can't boot the non-live Ubuntu) – Martín Gómez Aug 28 '15 at 12:53
  • sourceforge.net/projects/boot-repair-cd Download boot-repair and also unetbootin in windows. unetbootin.github.io – Ed Iglehart Aug 30 '15 at 23:31
  • sourceforge.net/projects/boot-repair-cd Download boot-repair and also unetbootin in windows. unetbootin.github.io Use unetbootin to prepare a bootable usb from the boot-repair iso Shut down windows, insert the usb, and power on while pressing f12. choose the usb and boot from that. It should lead you by the hand. Let me know how you get on. ed. – Ed Iglehart Aug 30 '15 at 23:41
  • P.S. If you go through the installation process again, when asked where to install bootloader, the answer is in all probability SDA, especially if you've only got one hard disk. – Ed Iglehart Aug 30 '15 at 23:53

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