After a debugging dialogue, the bug was found and squashed. The problem was some confusing data due to a floppy drive (a bug that only affects very old computers) in the function p_list_drives
in the program dus
:
grep -v zram --> grep -v -e zram -e ^fd
A new version can be installed via the following commands
sudo add-apt-repository ppa:mkusb/unstable
sudo apt-get update
sudo apt-get dist-upgrade
The current update (2017-04-02) installs mkusb version 12.0.9
Edit: After further testing (2017-04-03) this version is uploaded to the stable PPA, ppa:mkusb/ppa
and can be installed via the following 'standard' commands
sudo add-apt-repository ppa:mkusb/ppa
sudo apt-get update
sudo apt-get dist-upgrade
In your question you wrote:
6) I CAN'T install program, because I'm in a live USB mode, anyway,
I've tried to install (for using the programs that must be installed)
Ubuntu on my SSD but at the end, it tells me that there is a problem
with GRUB (my Ubuntu boot is in EFI mode), and I think that I can't
install grub because I'm in a liveUSB...
Fortunately things are better than what you thought. It is possible to install a program in a live system, and it can be used.
The installed program will survive as long as the live system is running. If you shutdown or reboot the live system, the installed program will be gone (but can be installed again). In other words, this is a useful option, if you intend to do something once. So it is possible to install mkusb or some other tool and use it to create a USB install drive for Windows 8.1.
There is also an alternative, that should work without installing anything.
See the following link to a 'Do It Yourself' method,
https://help.ubuntu.com/community/Installation/iso2usb/diy
If there are problems with this 'diy' method, mkusb could still work, due to the copying method via a tarball, as described by @MichaelBay in a comment and at this link.
Best Answer
Ubuntu 19.10 and later
The best application for making a bootable Ubuntu live USB from Windows is Rufus. The official ubuntu.com website recommends using Rufus instead of UNetbootin. Step-by-step instructions for creating a bootable Ubuntu live USB from Windows are at How to create a bootable USB stick on Windows.
Rufus persistent storage partition is supported in 19.10 and later. Please upgrade Rufus to version 3.9 or later.
Ubuntu 19.04 and earlier
mkusb is the most reliable tool for making an Ubuntu live USB with persistent file storage in 19.04 and earlier.