I encountered a bug described here [1] by Gawain Lynch. I will quote the content of that page: >I hit a rather interesting 'feature' in systemd recently where doing an ` su - ` and then running a GUI application before switching back and executing one as your normal user will cause GNOME shell to lock-up. > > Examining /var/log/messages I found a series of messages similar to: > > gnome-session[NNNN]: CRITICAL: unable to create file '/run/user/1000/dconf/user': > Permission denied. dconf will not work properly. > > [...] > > What in effect happens, is that the file /run/user/1000/dconf/user becomes owned by the root user > [...] > Fortunately the workaround is quite easy. Simply add this to the root users .bash_profile : > > export XDG_RUNTIME_DIR=/run/user/0 [1] http://gawainlynch.com/gnome-shell-crashes-after-su
Sorry, but random rants from the Internet are not the way to file bug reports. Anyway, I can't reproduce this. 1) su - 2) gedit 3) exit 4) gedit Nothing locks up, things work as expected.
When I said "I encountered" I meant that I actually experienced that bug myself, several times. It's only that the cited page (which I found searching for "/run/user/1000/dconf/user Permission denied" and "systemd" on Google) seems to give a reasonable explanation, though I can not yet confirm with absolute certainty that the workarround does the trick. To my knowledge, to reproduce this will have to follow a login/boot, so that no other GTK (dconf?) application ran before? I will try in more detail when I have time, in the meantime someone else may want to try.