[MULTI BOOT] How to dual boot with windows 10 on UEFI

[ZingyTomato]

Hi,
So I recently wanted to dual boot windows with kubuntu when I realized that it does not use the Calamares installer. So I am not really sure how to dual boot it although I am familiar with the process of assigning mount points etc.
Can somebody assist me with this?
Thanks

[jlittle]

(I've just done this.) My approach:

1. Backed up the Windows installation fully, a system backup and also a data oriented backup. Created the USB key it wanted me to.
2. Reduced the size of the main Windows partition, leaving the others alone. Some folks recommend doing this using Windows "Disk management", others say using Gparted is better. I mostly followed the this superuser.com answer, except that I had to defrag and use the windows event log (as explained in another answer) to identify the immovable file that was stopping the volume from being reduced as much as I wanted. It was a file used by the antivirus software, and I needed to disable it temporarily, defrag, reduce, and re-enable. Maybe using Gparted while booted from the installer USB with Windows shut down would have obviated that nuisance.
3. Booted the Kubuntu installer, and when it got to the storage chose the "manual" or "something else" option. I used the installer screen to create a big btrfs partition in the space left by reducing Windows, and set that as /. (I also made a swap partition out of habit, but that's not necessary these days.) Marked the EFI system partition to be used as such but didn't set it to be formatted.
4. Proceeded with the install.

Now you needn't use btrfs, and could go with ext4, which would be simpler. To get many of the benefits of btrfs you have to learn some stuff, but IMO it's well worth it, and ext4 and NTFS are just old technology. (That's not just my opinion, the maintainer of ext4 agrees, as do the Fedora and OpenSuse projects.)

[rustyjarz]

Hi,

I've just installed kubuntu 21.04 in a dual boot configuration with W10 EUFI mode, I see the boot menu option to boot into Ubuntu and when I try to boot to kubuntu all i see is a blank sreeen. kubuntu fails to laod up and I have no clue what the issue could be. I have successfully dual booted with ununtu cinnamon and wanted to switch to kubuntu but as said I can't or it won't boot.

(I've just done this.) My approach:

1. Backed up the Windows installation fully, a system backup and also a data oriented backup. Created the USB key it wanted me to.
2. Reduced the size of the main Windows partition, leaving the others alone. Some folks recommend doing this using Windows "Disk management", others say using Gparted is better. I mostly followed the this superuser.com answer, except that I had to defrag and use the windows event log (as explained in another answer) to identify the immovable file that was stopping the volume from being reduced as much as I wanted. It was a file used by the antivirus software, and I needed to disable it temporarily, defrag, reduce, and re-enable. Maybe using Gparted while booted from the installer USB with Windows shut down would have obviated that nuisance.
3. Booted the Kubuntu installer, and when it got to the storage chose the "manual" or "something else" option. I used the installer screen to create a big btrfs partition in the space left by reducing Windows, and set that as /. (I also made a swap partition out of habit, but that's not necessary these days.) Marked the EFI system partition to be used as such but didn't set it to be formatted.
4. Proceeded with the install.

Now you needn't use btrfs, and could go with ext4, which would be simpler. To get many of the benefits of btrfs you have to learn some stuff, but IMO it's well worth it, and ext4 and NTFS are just old technology. (That's not just my opinion, the maintainer of ext4 agrees, as do the Fedora and OpenSuse projects.)

[Qqmike]

I don't have much to add, really. I haven't done this since 18.04, and I use ext4. At the time, I wrote up what I did. I'll post that "how-to" here, just in case there's something in it that hits a chord:
https://www.kubuntuforums.net/showth...l=1#post418607
(I had no problems, at all, btw, fwiw)

[jlittle]

I've just installed kubuntu 21.04 in a dual boot configuration with W10 EUFI mode, I see the boot menu option to boot into Ubuntu and when I try to boot to kubuntu all i see is a blank sreeen. kubuntu fails to laod up and I have no clue what the issue could be.

Neither have I, sorry. All I can suggest is to try the recovery mode. There should be an "Advanced options for Ubuntu" item on the menu, then choose one saying "(recovery mode)" at the end. It might show you error messages that give a clue.