Hi and thanks for the link, was helpful.
Tried again and I succeeded.
It's a laptop running Windows 10 64bit on HDD with Optane Memory.
I'm aware that Windows 10 32bit and the Legacy Bios are not supported by this technology. I's fine and I just need to run that OS version.
Here what I did to do the job, that may help other people.
- disabeled Optane Memory within the Intel RST app and rebooted the PC (necessary step and that's why I couldn't install the OS at the first day because I didn't disable it).
- removed that RST app and all related apps (IDK if this was necessary or not)
- entered the BIOS and enabled the Legacy Bios mode and ran the OS setup as usual, done.