By the way, if 19.04 works, and 18.04 doesn't, it's possible there was a bug with some packages (such as ubiquity, kernel, etc.) associated to 18.04, and those bugs were fixed with 19.04.
By the way, if 19.04 works, and 18.04 doesn't, it's possible there was a bug with some packages (such as ubiquity, kernel, etc.) associated to 18.04, and those bugs were fixed with 19.04.