We have a cluster of Ubuntu 16 LTS machines that authenticate off of LDAP and have their home directories in a separate filer. Users can log into the terminal (Ctrl-Alt-F1) and can also log into the GUI (in this case, since it's Ubuntu 16, Unity.) However, no menu or dash appears. The contents of their ~/Desktop folder appear, but they can only right-click to get the menu, and the click-and-drag field. This problem does not happen for the guest user account -- they get the menu bar and dash.
DISPLAY=:0 ccsm & does not make the compiz configuration manager appear.
dconf reset -f /org/compiz gives the error message, "Cannot autolaunch D-Bus without X11 $Display".
startx results in a Unity session but with the same issue, where there is no menu bar or dash.
Since this ONLY happens to regular users, it was suggested to me that I look in /etc/pam.d for solutions, and while I added
session optional pam_systemd.so /etc/pam/common-session, this did not resolve the issue. However, PAM is a sprawling non-Euclidean horror and I may have missed something further in it, though I don't know what.
The test machine has been wiped and Ubuntu reinstalled several times. These are Dell OptiPlex 7050 with integrated Intel graphics, single-booting to Ubuntu (no other OS on them.)
Thank you very much for your time, and for any other help you can provide!