I have recently upgraded the workstations from Debian 9 to Debian 10. With the
old version people have been able to mount USB drives and play and record sound
(for video conferences). After the update neither of it works.

Remote user accounts

There have been some peculiarities with the user accounts, so perhaps that is
the source of the issue. We use NIS and NFS to provide user accounts and home
directories on all the machines. After the upgrade to Debian 10 I needed to add
a NIS to /etc/nsswitch.conf because they were on compat before and now
only had files. Also ypbind was not running because it no longer used
-broadcast as a default startup option. I added a new systemd file at
/etc/systemd/system/ypbind.service:

[Unit]
Description=ypbind
Wants=network-online.target nis.service
After=network-online.target nis.service

[Service]
Type=simple
ExecStart=/usr/sbin/ypbind -broadcast -foreground

[Install]
WantedBy=multi-user.target

With that the user accounts were there and the home directories as well. On the
command line I could also log in. But the LightDM display manager was still not
letting the users in. So in /etc/lightdm/lightdm.conf in section [LightDM]
I added the option greeter-show-manual-login = True and from then on the
remote users could log in. Some machines still had GDM as their default display manager, there the logins showed the same behavior that LightDM did before I changed the configuration. The password check passed, the screen might turn black for a brief moment and then the login screen is shown again. The same occurs when users have exceeded their quota and the files needed to establish the session (.Xauthority?) could not be created.

The peculiar thing is that when I am logged in via SSH and also on the actual
screen, these sessions show up properly with who:

$ who
ueding   pts/0        2019-08-26 12:42 (131.220.226.20)
ueding   tty7         2019-08-26 12:43 (:0)

But then at the same time the session is not listed with loginctl:

$ loginctl
No sessions.

When I do the same on my personal Fedora 30 laptop with local user accounts I
have this output of who:

$ who
mu       tty1         2019-08-25 10:33 (:0)
mu       pts/0        2019-08-25 10:34 (:0)
mu       pts/1        2019-08-26 12:08 (:0)
mu       pts/2        2019-08-26 12:14 (:0)
mu       pts/3        2019-08-26 12:42 (:0)
mu       pts/4        2019-08-26 12:38 (:0)
mu       pts/5        2019-08-26 12:55 (:0)

And also loginctl shows something sensible:

$ loginctl
SESSION  UID USER SEAT  TTY
      1 1000 mu   seat0    

1 sessions listed.

I have created a new local user account with UID 50000 on one of the Debian 10 workstations and found that I can log in, have the session show up in loginctl and also the removable media and sound issues described below are not there, sound and removable media works. So this definitely is an issue with the users coming from NIS.

The one thing that has hit me a few times so far is that for historical reasons
the user ids that we have given out start with 500. But my user ueding has
uid 1085, so even if that was a problem with accounts not being listed, this
account should be fine because the default starting values for user ids which
are not considered system users is 1000.

I do not have sufficient experience but I just have the feeling that somehow
the user accounts are not fully in the system, that there is just something
still missing.

One user with uid 536 had to enter his GNOME keychain password after login. I
am not sure whether he has different passwords there, but it could as well be
that it was not unlocked during startup. This might not mean anything, though.

auth.log

With the current state this is everything that shows up in /var/log/auth.log since booting the machine, connecting as root via SSH to retrieve the log and logging in on the machine itself with my NIS user. Also the monitoring user has logged in via SSH to retrieve some information for my monitoring system.

Sep  3 12:45:42 helios systemd-logind[497]: New seat seat0.
Sep  3 12:45:42 helios systemd-logind[497]: Watching system buttons on /dev/input/event1 (Power Button)
Sep  3 12:45:42 helios systemd-logind[497]: Watching system buttons on /dev/input/event0 (Power Button)
Sep  3 12:45:42 helios systemd-logind[497]: Watching system buttons on /dev/input/event3 (Cherry USB keyboard)
Sep  3 12:45:42 helios systemd-logind[497]: Watching system buttons on /dev/input/event4 (Cherry USB keyboard System Control)
Sep  3 12:45:46 helios sshd[650]: Server listening on 0.0.0.0 port 22.
Sep  3 12:45:46 helios sshd[650]: Server listening on :: port 22.
Sep  3 12:45:57 helios lightdm: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Sep  3 12:45:57 helios systemd-logind[497]: New session c1 of user lightdm.
Sep  3 12:45:57 helios systemd: pam_unix(systemd-user:session): session opened for user lightdm by (uid=0)
Sep  3 12:47:08 helios sshd[1339]: rexec line 16: Deprecated option UsePrivilegeSeparation
Sep  3 12:47:08 helios sshd[1339]: rexec line 19: Deprecated option KeyRegenerationInterval
Sep  3 12:47:08 helios sshd[1339]: rexec line 20: Deprecated option ServerKeyBits
Sep  3 12:47:08 helios sshd[1339]: rexec line 31: Deprecated option RSAAuthentication
Sep  3 12:47:08 helios sshd[1339]: rexec line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:08 helios sshd[1339]: Connection closed by 131.220.226.3 port 39932 [preauth]
Sep  3 12:47:16 helios sshd[1341]: rexec line 16: Deprecated option UsePrivilegeSeparation
Sep  3 12:47:16 helios sshd[1341]: rexec line 19: Deprecated option KeyRegenerationInterval
Sep  3 12:47:16 helios sshd[1341]: rexec line 20: Deprecated option ServerKeyBits
Sep  3 12:47:16 helios sshd[1341]: rexec line 31: Deprecated option RSAAuthentication
Sep  3 12:47:16 helios sshd[1341]: rexec line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:16 helios sshd[1341]: reprocess config line 31: Deprecated option RSAAuthentication
Sep  3 12:47:16 helios sshd[1341]: reprocess config line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:19 helios sshd[1341]: Accepted password for root from 131.220.226.160 port 44060 ssh2
Sep  3 12:47:19 helios sshd[1341]: pam_unix(sshd:session): session opened for user root by (uid=0)
Sep  3 12:47:19 helios systemd-logind[497]: New session 2 of user root.
Sep  3 12:47:19 helios systemd: pam_unix(systemd-user:session): session opened for user root by (uid=0)
Sep  3 12:47:20 helios sshd[1367]: rexec line 16: Deprecated option UsePrivilegeSeparation
Sep  3 12:47:20 helios sshd[1367]: rexec line 19: Deprecated option KeyRegenerationInterval
Sep  3 12:47:20 helios sshd[1367]: rexec line 20: Deprecated option ServerKeyBits
Sep  3 12:47:20 helios sshd[1367]: rexec line 31: Deprecated option RSAAuthentication
Sep  3 12:47:20 helios sshd[1367]: rexec line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:20 helios sshd[1367]: reprocess config line 31: Deprecated option RSAAuthentication
Sep  3 12:47:20 helios sshd[1367]: reprocess config line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:20 helios sshd[1367]: Accepted publickey for monitoring from 131.220.226.3 port 39970 ssh2: RSA SHA256:ulxULyONiGRB8VUFctWd/WSBcRxjGX+5Dq/IXyZS+gI
Sep  3 12:47:20 helios sshd[1367]: pam_unix(sshd:session): session opened for user monitoring by (uid=0)
Sep  3 12:47:20 helios systemd-logind[497]: New session 4 of user monitoring.
Sep  3 12:47:20 helios systemd: pam_unix(systemd-user:session): session opened for user monitoring by (uid=0)
Sep  3 12:47:20 helios sshd[1385]: Received disconnect from 131.220.226.3 port 39970:11: disconnected by user
Sep  3 12:47:20 helios sshd[1385]: Disconnected from user monitoring 131.220.226.3 port 39970
Sep  3 12:47:20 helios sshd[1367]: pam_unix(sshd:session): session closed for user monitoring
Sep  3 12:47:20 helios systemd-logind[497]: Session 4 logged out. Waiting for processes to exit.
Sep  3 12:47:20 helios systemd-logind[497]: Removed session 4.
Sep  3 12:47:30 helios systemd: pam_unix(systemd-user:session): session closed for user monitoring
Sep  3 12:47:32 helios sshd[1398]: rexec line 16: Deprecated option UsePrivilegeSeparation
Sep  3 12:47:32 helios sshd[1398]: rexec line 19: Deprecated option KeyRegenerationInterval
Sep  3 12:47:32 helios sshd[1398]: rexec line 20: Deprecated option ServerKeyBits
Sep  3 12:47:32 helios sshd[1398]: rexec line 31: Deprecated option RSAAuthentication
Sep  3 12:47:32 helios sshd[1398]: rexec line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:32 helios sshd[1398]: reprocess config line 31: Deprecated option RSAAuthentication
Sep  3 12:47:32 helios sshd[1398]: reprocess config line 38: Deprecated option RhostsRSAAuthentication
Sep  3 12:47:32 helios sshd[1398]: Accepted publickey for monitoring from 131.220.226.3 port 39992 ssh2: RSA SHA256:ulxULyONiGRB8VUFctWd/WSBcRxjGX+5Dq/IXyZS+gI
Sep  3 12:47:32 helios sshd[1398]: pam_unix(sshd:session): session opened for user monitoring by (uid=0)
Sep  3 12:47:32 helios systemd-logind[497]: New session 6 of user monitoring.
Sep  3 12:47:32 helios systemd: pam_unix(systemd-user:session): session opened for user monitoring by (uid=0)
Sep  3 12:47:32 helios sshd[1416]: Received disconnect from 131.220.226.3 port 39992:11: disconnected by user
Sep  3 12:47:32 helios sshd[1416]: Disconnected from user monitoring 131.220.226.3 port 39992
Sep  3 12:47:32 helios sshd[1398]: pam_unix(sshd:session): session closed for user monitoring
Sep  3 12:47:32 helios systemd-logind[497]: Session 6 logged out. Waiting for processes to exit.
Sep  3 12:47:32 helios systemd-logind[497]: Removed session 6.
Sep  3 12:47:42 helios systemd: pam_unix(systemd-user:session): session closed for user monitoring
Sep  3 12:48:14 helios lightdm: pam_unix(lightdm-greeter:session): session closed for user lightdm
Sep  3 12:48:14 helios systemd-logind[497]: Removed session c1.
Sep  3 12:48:14 helios lightdm: pam_unix(lightdm:session): session opened for user ueding by (uid=0)
Sep  3 12:48:14 helios lightdm: pam_systemd(lightdm:session): Failed to create session: No such file or directory
Sep  3 12:48:24 helios systemd: pam_unix(systemd-user:session): session closed for user lightdm

I guess the second last line is the really interesting one.

Accompanying syslog

Sep 04 14:10:10 helios systemd[1]: session-c3.scope: Killing process 28814 (lightdm) with signal SIGTERM.
Sep 04 14:10:10 helios systemd[1]: session-c3.scope: Killing process 28829 (lightdm-gtk-gre) with signal SIGTERM.
Sep 04 14:10:10 helios systemd[1]: Stopping Session c3 of user lightdm.
Sep 04 14:10:10 helios lightdm[28814]: pam_unix(lightdm-greeter:session): session closed for user lightdm
Sep 04 14:10:10 helios systemd[1]: session-c3.scope: Succeeded.
Sep 04 14:10:10 helios systemd[1]: Stopped Session c3 of user lightdm.
Sep 04 14:10:10 helios systemd-logind[497]: Removed session c3.
Sep 04 14:10:10 helios lightdm[28869]: pam_unix(lightdm:session): session opened for user ueding by (uid=0)
Sep 04 14:10:10 helios lightdm[28869]: pam_systemd(lightdm:session): Failed to create session: No such file or directory
Sep 04 14:10:10 helios lightdm[28869]: Failed to open CK session: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ConsoleKit was not provided by any .service files
Sep 04 14:10:10 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.a11y.Bus' requested by ':1.3' (uid=1085 pid=28933 comm="xfce4-session ")
Sep 04 14:10:10 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.a11y.Bus'
Sep 04 14:10:10 helios org.a11y.Bus[28914]: dbus-daemon[28940]: Activating service name='org.a11y.atspi.Registry' requested by ':1.0' (uid=1085 pid=28933 comm="xfce4-session ")
Sep 04 14:10:10 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.xfce.Xfconf' requested by ':1.3' (uid=1085 pid=28933 comm="xfce4-session ")
Sep 04 14:10:10 helios org.a11y.Bus[28914]: dbus-daemon[28940]: Successfully activated service 'org.a11y.atspi.Registry'
Sep 04 14:10:10 helios org.a11y.Bus[28914]: SpiRegistry daemon is running with well-known name - org.a11y.atspi.Registry
Sep 04 14:10:10 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.xfce.Xfconf'
Sep 04 14:10:11 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.Daemon' requested by ':1.9' (uid=1085 pid=28954 comm="Thunar --sm-client-id 2e9ea3a26-363a-4e06-b723-b6d")
Sep 04 14:10:11 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.Daemon'
Sep 04 14:10:11 helios org.gtk.vfs.Daemon[28914]: fusermount: failed to open mountpoint for reading: Permission denied
Sep 04 14:10:11 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.freedesktop.thumbnails.Thumbnailer1' requested by ':1.16' (uid=1085 pid=28972 comm="xfdesktop --display :0.0 --sm-client-id 24fe00ba0-")
Sep 04 14:10:11 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.freedesktop.Notifications' requested by ':1.20' (uid=1085 pid=28988 comm="xfce4-power-manager --restart --sm-client-id 270b9")
Sep 04 14:10:11 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.freedesktop.Notifications'
Sep 04 14:10:12 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.freedesktop.Tracker1' requested by ':1.28' (uid=1085 pid=29060 comm="gdbus call -e -d org.freedesktop.DBus -o /org/free")
Sep 04 14:10:12 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='ca.desrt.dconf' requested by ':1.29' (uid=1085 pid=29045 comm="light-locker ")
Sep 04 14:10:12 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'ca.desrt.dconf'
Sep 04 14:10:12 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.freedesktop.Tracker1'
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer /usr/bin/gdk-pixbuf-thumbnailer -s %s %u %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer evince-thumbnailer -s %s %u %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer gnome-thumbnail-font --size %s %u %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer /usr/bin/gdk-pixbuf-thumbnailer -s %s %u %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer atril-thumbnailer -s %s %u %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer /usr/share/blender/scripts/blender-thumbnailer.py %i %o
Sep 04 14:10:12 helios org.freedesktop.thumbnails.Thumbnailer1[28914]: Registered thumbailer /usr/bin/totem-video-thumbnailer -s %s %u %o
Sep 04 14:10:12 helios kernel: traps: light-locker[29045] trap int3 ip:7f6a78690c75 sp:7ffec8e2fea0 error:0 in libglib-2.0.so.0.5800.3[7f6a78658000+7e000]
Sep 04 14:10:12 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gnome.evolution.dataserver.Sources5' requested by ':1.38' (uid=1085 pid=29044 comm="/usr/lib/evolution/evolution-data-server/evolution")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gnome.OnlineAccounts' requested by ':1.40' (uid=1085 pid=29094 comm="/usr/lib/evolution/evolution-source-registry ")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gnome.evolution.dataserver.Sources5'
Sep 04 14:10:13 helios goa-daemon[29107]: goa-daemon version 3.30.1 starting
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gnome.Identity' requested by ':1.41' (uid=1085 pid=29107 comm="/usr/lib/gnome-online-accounts/goa-daemon ")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gnome.OnlineAccounts'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gnome.Identity'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gnome.evolution.dataserver.Calendar7' requested by ':1.38' (uid=1085 pid=29044 comm="/usr/lib/evolution/evolution-data-server/evolution")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.UDisks2VolumeMonitor' requested by ':1.23' (uid=1085 pid=28986 comm="/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd ")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.UDisks2VolumeMonitor'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.AfcVolumeMonitor' requested by ':1.23' (uid=1085 pid=28986 comm="/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd ")
Sep 04 14:10:13 helios org.gtk.vfs.AfcVolumeMonitor[28914]: Volume monitor alive
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.AfcVolumeMonitor'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gnome.evolution.dataserver.Calendar7'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gnome.evolution.dataserver.AddressBook9' requested by ':1.43' (uid=1085 pid=29125 comm="/usr/lib/evolution/evolution-calendar-factory ")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.GoaVolumeMonitor' requested by ':1.23' (uid=1085 pid=28986 comm="/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd ")
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gnome.evolution.dataserver.AddressBook9'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.GoaVolumeMonitor'
Sep 04 14:10:13 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.MTPVolumeMonitor' requested by ':1.23' (uid=1085 pid=28986 comm="/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd ")
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.MTPVolumeMonitor'
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.GPhoto2VolumeMonitor' requested by ':1.23' (uid=1085 pid=28986 comm="/usr/lib/x86_64-linux-gnu/tumbler-1/tumblerd ")
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.GPhoto2VolumeMonitor'
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.freedesktop.thumbnails.Thumbnailer1'
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Activating service name='org.gtk.vfs.Metadata' requested by ':1.14' (uid=1085 pid=28972 comm="xfdesktop --display :0.0 --sm-client-id 24fe00ba0-")
Sep 04 14:10:14 helios dbus-daemon[28914]: [session uid=1085 pid=28912] Successfully activated service 'org.gtk.vfs.Metadata'
Sep 04 14:10:20 helios systemd[1]: Stopping User Manager for UID 116...
Sep 04 14:10:20 helios systemd[28818]: Stopping D-Bus User Message Bus...
Sep 04 14:10:20 helios gvfsd[28842]: A connection to the bus can't be made
Sep 04 14:10:20 helios systemd[28818]: Stopping Accessibility services bus...
Sep 04 14:10:20 helios systemd[28818]: Stopping Virtual filesystem service...
Sep 04 14:10:20 helios systemd[28818]: Stopped target Default.
Sep 04 14:10:20 helios systemd[28818]: gvfs-daemon.service: Main process exited, code=killed, status=15/TERM
Sep 04 14:10:20 helios systemd[28818]: at-spi-dbus-bus.service: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Stopped Accessibility services bus.
Sep 04 14:10:20 helios systemd[28818]: dbus.service: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Stopped D-Bus User Message Bus.
Sep 04 14:10:20 helios systemd[1]: run-user-116-gvfs.mount: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: run-user-116-gvfs.mount: Succeeded.
Sep 04 14:10:20 helios systemd[25779]: run-user-116-gvfs.mount: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: gvfs-daemon.service: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Stopped Virtual filesystem service.
Sep 04 14:10:20 helios systemd[28818]: Stopped target Basic System.
Sep 04 14:10:20 helios systemd[28818]: Stopped target Sockets.
Sep 04 14:10:20 helios systemd[28818]: gpg-agent-browser.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed GnuPG cryptographic agent and passphrase cache (access for web browsers).
Sep 04 14:10:20 helios systemd[28818]: gpg-agent.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed GnuPG cryptographic agent and passphrase cache.
Sep 04 14:10:20 helios systemd[28818]: gpg-agent-ssh.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed GnuPG cryptographic agent (ssh-agent emulation).
Sep 04 14:10:20 helios systemd[28818]: dirmngr.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed GnuPG network certificate management daemon.
Sep 04 14:10:20 helios systemd[28818]: gpg-agent-extra.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed GnuPG cryptographic agent and passphrase cache (restricted).
Sep 04 14:10:20 helios systemd[28818]: pulseaudio.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed Sound System.
Sep 04 14:10:20 helios systemd[28818]: Stopped target Timers.
Sep 04 14:10:20 helios systemd[28818]: Stopped target Paths.
Sep 04 14:10:20 helios systemd[28818]: dbus.socket: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Closed D-Bus User Message Bus Socket.
Sep 04 14:10:20 helios systemd[28818]: Reached target Shutdown.
Sep 04 14:10:20 helios systemd[28818]: systemd-exit.service: Succeeded.
Sep 04 14:10:20 helios systemd[28818]: Started Exit the Session.
Sep 04 14:10:20 helios systemd[28818]: Reached target Exit the Session.
Sep 04 14:10:20 helios systemd[28819]: pam_unix(systemd-user:session): session closed for user lightdm
Sep 04 14:10:20 helios systemd[1]: user@116.service: Succeeded.
Sep 04 14:10:20 helios systemd[1]: Stopped User Manager for UID 116.
Sep 04 14:10:20 helios systemd[1]: Stopping User Runtime Directory /run/user/116...
Sep 04 14:10:20 helios systemd[25779]: run-user-116.mount: Succeeded.
Sep 04 14:10:20 helios systemd[1]: run-user-116.mount: Succeeded.
Sep 04 14:10:20 helios systemd[1]: user-runtime-dir@116.service: Succeeded.
Sep 04 14:10:20 helios systemd[1]: Stopped User Runtime Directory /run/user/116.
Sep 04 14:10:20 helios systemd[1]: Removed slice User Slice of UID 116.

Present conclusion

I feel that there is something that prevents users from becoming “fully logged
in”, in a sense that they do have an Xfce session and can see their home
directories, but not enough to be registered with the “fancy” stuff like
logind or Pulse Audio. Or perhaps they are missing a special user group. A local user account on of the machines works just as expected, so this definitely is some issue with the user accounts in general and not with one of the symptoms (loginctl output, sound, removable media).

I cannot really grasp this and I am not sure where exactly I should look.
Pointers or (hopefully) solutions are very much welcome!