I am trying to install a 14.04.5 64 bits Ubuntu in a machine with several partitions, one of which is already running a 12.04 64 bits Ubuntu, into one that is empty and formatted as ext4. I have created a bootable Ubuntu USB following the instructions of https://tutorials.ubuntu.com/tutorial/tutorial-create-a-usb-stick-on-windows#3, but when I try to install I get an error message that says:
No DEFAULT or UI configuration directive found! boot: _
and I do not know how to follow.
I have also tried to use Universal USB installer but the result is that the screen remains blank for eternity just with the prompt, which does not admit any command. I have changed the name of the isolinux files and folder to syslinux, as I have seen in other threads with similar isues, but to no avail.
Rather than because of the tool, I believe this is related to the fact that when I have the USB formatted to have the Ubuntu distribution installed in it, it is done so as FAT32, rather than ext4, so perhaps it is not recognized at all. Is there any way to me to change the format of the USB from FAT32 to ext4, or this is not related at all? I understand (correct me if I am wrong) that FAT32 is an obsolete format and ext4 should be used for Ubuntu instead. I am toatlly open to use an ext4 USB bootable stick, but I do not know any tool that may do the job (rufus 2.15 and universal USB installer 1.9.7.8 do not offer ext4 as an option).
Any help to solve this will be more than welcome.