If after entering username/password you see a small window (with a going back and forth blue “slider”) saying:
“Completing post install setup”
most likely svc:/system/postrun/default service is not running.
Check the status:
# svcs -vx postrun
and enable it if it’s disabled (for example, after a system upgrade)
# svcadm enable postrun
Related system packages:
# pkginfo | fgrep postrun
GNOME2 SUNWpostrun Delayed execution environment for procedural package scripts
GNOME2 SUNWpostrun-root Delayed execution environment for procedural package scripts – / filesystem
GNOME2 SUNWpostrun Delayed execution environment for procedural package scripts
GNOME2 SUNWpostrun-root Delayed execution environment for procedural package scripts – / filesystem