fungal_net wroteWelcome
Some analysis with many unknowns.
Starting your X/wm session with startx (or xinit) your ~/.xinitrc is read.
If you had success in running "without" a user tree the problem you see at the end is not because you didn't have a user tree but that the command in .xinitrc (I think) that brought up the tree and services and brought it down on logout, doesn't find a tree.
If you simply created a tree that means that a boot-user tree and corresponding module for that user exists and the tree is enabled, otherwise the user tree wouldn't run.
What/how did you install the system and what does % 66-intree -g and % sudo 66-intree -g show?
Since I don't know what you have done I am suspecting you followed the instructions for creating a boot-user module and it created .xinitrc and .xsession in which the default user command to start user trees exists. Since you didn't have any it produced such an error.
Are you using/needing consolekit consoletracker dbus, etc.??
I install obarun following the wiki.
% 66-intree -g
Name : base
Initialized : no
Enabled : yes
Starts after : None
Current : yes
Allowed : fysnin
Symlinks : svc->source db->source
Contents : /
└─None
% sudo 66-intree -g
Name : boot
Initialized : yes
Enabled : no
Starts after : None
Current : no
Allowed : root
Symlinks : svc->source db->source
Contents : /
├─(195,Enabled,classic) tty-earlier@ tty12
├─(up,Enabled,oneshot) system-hostname
├─(up,Enabled,oneshot) mount-run
├─(up,Enabled,oneshot) populate-run
├─(up,Enabled,oneshot) mount-tmp
├─(up,Enabled,oneshot) populate-tmp
├─(up,Enabled,oneshot) mount-proc
├─(up,Enabled,oneshot) mount-sys
├─(up,Enabled,oneshot) populate-sys
├─(up,Enabled,oneshot) mount-dev
├─(up,Enabled,oneshot) mount-pts
├─(up,Enabled,oneshot) mount-shm
├─(up,Enabled,oneshot) populate-dev
├─(up,Enabled,oneshot) mount-cgroups
├─(up,Enabled,bundle) 00
├─(up,Enabled,bundle) all-Mount
├─(up,Enabled,oneshot) system-hwclock
├─(up,Enabled,oneshot) modules-kernel
├─(up,Enabled,oneshot) system-random
├─(up,Enabled,oneshot) modules-system
├─(up,Enabled,oneshot) system-sysctl
├─(239,Enabled,longrun) udevd-log
├─(404,Enabled,longrun) udevd
├─(up,Enabled,oneshot) udevadm
├─(up,Enabled,oneshot) system-fontnkey
├─(up,Enabled,oneshot) system-fsck
├─(up,Enabled,oneshot) mount-fstab
├─(up,Enabled,bundle) all-System
├─(up,Enabled,oneshot) mount-rw
├─(up,Enabled,oneshot) mount-swap
├─(up,Enabled,oneshot) mount-netfs
├─(up,Enabled,oneshot) local-loop
├─(up,Enabled,oneshot) local-sethostname
├─(up,Enabled,oneshot) local-time
├─(up,Enabled,oneshot) local-authfiles
├─(up,Enabled,oneshot) local-tmpfiles
├─(up,Enabled,oneshot) local-dmesg
├─(up,Enabled,bundle) all-Local
├─(up,Enabled,oneshot) all-Runtime
├─(up,Enabled,bundle) All
├─(752,Enabled,longrun) tty-rc@ tty2
├─(751,Enabled,longrun) tty-rc@ tty1
├─(750,Enabled,longrun) tty-rc@ tty3
└─(up,Enabled,module) boot@ system
Name : root
Initialized : yes
Enabled : yes
Starts after : None
Current : yes
Allowed : root
Symlinks : svc->source db->source
Contents : /
├─(666,Enabled,classic) dhcpcd-log
└─(667,Enabled,classic) dhcpcd
Name : boot-user
Initialized : yes
Enabled : yes
Starts after : root
Current : no
Allowed : root
Symlinks : svc->source db->source
Contents : /
├─(up,Enabled,oneshot) setenv@ fysnin
├─(701,Enabled,longrun) svscan@ fysnin-log
├─(739,Enabled,longrun) svscan@ fysnin
├─(up,Enabled,module) scandir@ fysnin
├─(up,Enabled,oneshot) mount-run@ fysnin
└─(up,Enabled,module) boot-user@ fysnin