Inicialização dupla UEFI Windows10 / Ubuntu

Question

De acordo com as configurações do sistema, estou trabalhando em um UEFI do Windows 10 BIOS, não no Legacy. Se eu tentar instalar o Ubuntu como UEFI, no caso de um disco de pré-formatação 0 aparecer um erro:

This machine's firmware has started the installer in UEFI mode but it looks like there may be existing operating systems already installed using "BIOS compatibility mode". If you continue to install Debian in UEFI mode, it might be difficult to reboot the machine into any BIOS-mode operating systems later.

Se eu não fizer uma pré-formatação, não obtenho a opção de instalação ao lado do Windows, o que está faltando?

Esta é minha sudo parted -l output:

Model: ATA ST1000LM035-1RK1 (scsi)  
Disk /dev/sda: 1000GB  
Sector size (logical/physical): 512B/4096B  
Partition Table: gpt  
Disk Flags:   
Number  Start   End    Size   File system  Name                          Flags  
1      1049kB  135MB  134MB               Microsoft reserved partition  msftres  
2      135MB   674GB  674GB  ntfs         Basic data partition          msftdata  
Model: SCSI DISK (scsi)  
Disk /dev/sdb: 16.0GB   
Sector size (logical/physical): 512B/512B  
Partition Table: gpt  

Disk Flags:   
Number  Start   End     Size    File system  Name                  Flags  
1      1049kB  16.0GB  16.0GB  fat32        Microsoft Basic Data  msftdata

There is no trace of Disk1, but I have no problem in booting Windows, whose OS is installed in Disk1. As for 'fdisk -l' :  

Disk /dev/loop0: 1.3 GiB, 1425731584 bytes, 2784632 sectors  
Units: sectors of 1 * 512 = 512 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors  
Units: sectors of 1 * 512 = 512 bytes  
Sector size (logical/physical): 512 bytes / 4096 bytes  
I/O size (minimum/optimal): 4096 bytes / 4096 bytes  
Disklabel type: gpt
Disk identifier: 70EE78E8-75FE-442A-B477-A13CE5E2ED24  

Device      Start        End    Sectors   Size Type  
/dev/sda1    2048     264191     262144   128M Microsoft reserved  
/dev/sda2  264192 1317378047 1317113856 628.1G Microsoft basic data  
Disk /dev/sdb: 14.9 GiB, 15955173376 bytes, 31162448 sectors  
Units: sectors of 1 * 512 = 512 bytes  
Sector size (logical/physical): 512 bytes / 512 bytes  
I/O size (minimum/optimal): 512 bytes / 512 bytes  
Disklabel type: gpt  
Disk identifier: 4CB04652-18BC-471A-B3F4-33CC33844705  
Device     Start      End  Sectors  Size Type  
/dev/sdb1   2048 31162414 31160367 14.9G Microsoft basic data  

Este é o meu esquema de partição do Gerenciador de Disco do Windows.

^{(Cliquenaimagemparaampliar)}

Estaéaminhainformaçãodosistema.