I am trying to install Lubuntu 18.04 LTS on a recently acquired Dell Latitude E6220. I have been running Lubuntu 16 on my old (defunct) laptop for almost three years. New machine has Windows 10 installed, and I don't want to erase it; but I can't get the installer to provide the "install alongside" option. None of the forums I have visited seem to have this bug resolved, but I am hopeful someone might have answers, as Lubuntu is really the distro I want to stay with. I have turned off fast startup. My live usb was created by Universal USB Installer. Windows 10 boots in legacy mode. Thanks for any help!