Linux Mint Installation (Partition)

It says: "The partition /dev/sdb5 assigned to / starts with an offset of 3584 bytes from the minimum alignment for this disk, which can have significant performance implications.

Since you are formatting this partition, you should address this issue now by realigning the partition as it will be difficult to modify later. To do this, you need to go back to the partitioning menu, delete the partition, and recreate it in the same place with the same settings. This will ensure that it starts in a suitable location for this disk."

Thank you for your quick response.

The partition is slightly misaligned, which may slow down the system.
Do as instructed in the message:
Cancel the installation, launch the gparted utility, and delete the sda5 partition before creating a new one in the freed space. It will be automatically aligned. Then, restart the installation.

Hi,

Normal...

You're trying to delete the partition from which your Live USB is running...

What exactly are you trying to do?

Because you mention wanting to install it on an external hard drive... but right now, you are installing it on the USB stick.

It is impossible for me to delete the partition :(

Because it is currently mounted...
First click on "Unmount" and you will see that the "Delete" option will become available.

I'm sorry, but I can't assist with that.

The partition sda1 does not belong to your external disk.
Connect this external disk and type the command:

sudo parted -l

(letter L) in the terminal and paste the result here.

There's something I'm missing: if sda1 is the root partition of your live session, unmount cannot work and delete cannot appear since the partition is in use.

Diskpart, for installing Linux, it doesn't matter. Linux has its own tools. Moreover, the NTFS format is not suitable at all: Linux has its own partition formats. Generally, the ext4 format is chosen, and only a Linux tool can format the partition in this format.
Given the difficulties you are encountering, you should first study this seriously:
http://linuxmint-installation-guide.readthedocs.io/en/latest/install.html

Then, with the partition management tool of Linux, called gparted, which is present on your live USB, you will need to create a small swap partition (2 Go) at the end of the disk, it will be called sdb2, and you will give it the format "linux-swap", while the remainder sdb1 should have the ext4 format. (We will skip the /home partition to simplify.)
If you cannot create a swap partition, we will create a swap file at the end of the installation to replace it.

When you reach this screen:
http://linuxmint-installation-guide.readthedocs.io/en/latest/_images/installer-partitions.en.png
You will choose /dev/sdb1 as the root partition
Double-click on it, and on this screen
http://linuxmint-installation-guide.readthedocs.io/en/latest/_images/installer-partition.en.png
You complete it as in the example ("/", ext4 format, check format) after validation, you return to the previous screen and modify the bottom line:
"Device where the boot loader will be installed" you indicate /dev/sdb1
And you finish the installation.

Upon reboot, remove your USB key, display the boot menu and choose your USB disk to boot the installed system and get back to me if you couldn’t create a swap partition; we will solve this problem then.

EDIT:
Important: These instructions are only valid if your PC boots in legacy mode and not in UEFI mode.
If you cannot switch the BIOS to legacy mode, you will need to proceed differently, and it's not worth attempting this installation.

Hello and happy new year,

Look at the little stars in the result of list disk. Both disks are in gpt. So, PC is in uefi.

Happy New Year to you too.
Not at all: look at the result of fdisk:
Partition Table: msdos
The disk is in msdos format... but its screenshot does not match the result of the parted command...

However, if the BIOS is set to UEFI, it's normal that it doesn't work.

Clearly, the screenshot does not match his PC, indeed. Let him manage if he confuses us.