"Is it a kernel crash? Or only about graphics / desktop?" Is it no kernel crash!!! I tried a ssh-connection from my laptop to leap15.5-PC This connection is stable after crash. The X-server is running and after any time the green-Display will be black and, if the mouse is moved, green again. Sorry this behaviour was new for me. Pleas show the attachment "dmseg-report-after-crash" , made on ssh-session.