Comment # 3 on bug 1210031 from Carlos Robinson

No, the issue is happening before I did a tar backup copy of the directory (in
the other machine, I did not do a backup). I did that backup/restore only
yesterday. But the entire {home} directory was cloned from another machine (in
the machine, this past summer, it happened to two brand new users).

Google suggests (yr 2011): "This apparently happens when xfce4 has trouble
shutting down a session. When this happens, the way I fix it is to delete the
.cache directory."

https://bugzilla.xfce.org/show_bug.cgi?id=7687



I will try your method the next time it happens.

I just booted the machine now, no failure. Rebooting. Rebooting. Rebooting.

Well, today it doesn't want to cooperate.