John van Spaandonk wrote: > root@Marius:~# xhost +root > Xlib: connection to ":0.0" refused by server > Xlib: No protocol specified > > xhost: unable to open display ":0" > root@Marius:~# Did whoever started the X server give that command? Try "xhost +marius" as that user, before su'ing to root. I get "bad hostname" with user names like +root.