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I want to configure dual boot with Ubuntu 19.04 and Windows 10 in my laptop.

When I read about it, I always see that people install Windows 10 first and then install Ubuntu. Why is that?

Zanna
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Keith Brabant
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    *I always see that they install Windows 10 first and then install Ubuntu. Why is that?* Short Answer: Windows messes up GRUB. – Kulfy May 24 '19 at 14:32
  • "they install Windows 10 first and then install Ubuntu" Not entirely correct: it is easier to have the LAST ONE installed to be a Linux OS. So Ubuntu, Windows, Ubuntu works too as the last one will correctly add grub – Rinzwind May 24 '19 at 15:09
  • @Rinzwind although windows installer get confused in the case where 1st ubuntu was on hard drive A, windows on hard drive B, it will put an efi partition and bootloader on both drive A and B which will cause it difficulties booting after you added the second ubuntu. – tatsu May 24 '19 at 15:11

2 Answers2

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Because Windows acts as if other OSes do not exist during it's install process and will destroy the other present operating systems.

If you install Windows first and then proceed to install Ubuntu after it, Ubuntu will correctly detect Windows and add it to the boot list A.K.A. "bootloader", in this case GRUB, and dual boot will correctly function.

Quick note though, for best results, after finishing the Windows installation run:

powercfg -h off

in an administrator Powershell or cmd

This will make sure Windows does not prevent Ubuntu from installing by locking the drives on shutdown/reboot/hibernate.

Zanna
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tatsu
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  • Oh ok. Thank you. Thanks everyone. So, when I install Ubuntu (after Windows), Ubuntu's GRUB will not 'delete' Windows's bootloader but will replace it with GRUB and will list Windows's bootloader in Grub. Right ?

    If I remember correctly, windows bootloader is called Boot manager.

     – Keith Brabant May 24 '19 at 15:03
  • no, even better! Grub get's to have it's little home and windows bootloader gets to keep it's little home. nobody gets moved or deleted. grub gets loaded first, and if you select windows from that list you actually get taken to the windows bootloader. by default windows bootloader has no other options and boots windows imediately, but say you configured it to have more boot options, you'd be greeted by the windows bootloader list. if this answer helped you out you can mark it as the answer with the check mark. – tatsu May 24 '19 at 15:07
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It is because it makes life easier. If Windows is installed after, you have to reload the Linux install dvd/usb, download bootrepair and reinstall grub (might have to do this after every Windows upgrade). If you are unlucky, Windows might even mess up the Linux partition badly.

Zanna
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crip659
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    Only if BIOS type install on one drive. If UEFI you may have to change boot order in UEFI or in Ubuntu with efibootmgr. Part of why new system should use UEFI installs. But you must always be consistent in how you boot as UEFI can boot in either UEFI or BIOS/CSM/Legacy boot mode. And how you boot install media for both Windows & Ubuntu UEFI or BIOS is then how it installs. And you really want both systems in same boot mode. – oldfred May 24 '19 at 16:12
  • Just did an install of Windows after Ubuntu and windows did not mess up grub, most of my info is from using/reading problems with BIOS type. Glad it is better now. – crip659 May 29 '19 at 16:58