On Friday August 17 2018 15:28:22 dep wrote: > when i select plasma at the login screen, all seems to go well but for the > appearance not of plasma but of a black screen with a mouse cursor. no ... > anybody know what's happening and how to fix it? Sadly no, but I'm afraid this is more or less the kind of symptom I've always had when I tried to start a different DE in Kubuntu, including when there was still an official [K]Ubuntu Neon5 project for 14.04 . Have you tried logging into a virtual terminal and then starting the new environment by hand (or simply running `startx`)? That often gives a bit more helpful output. R