Sometimes, after a fresh boot and login, I find that the appearance has changed. It seems to be some default theme and when I open the Appearance Preferences, I get the message:
Unable to start the settings manager 'gnome-settings-daemon'.
Without the GNOME settings manager running, some preferences may not take effect. This could indicate a problem with DBus, or a non-GNOME (e.g. KDE) settings manager may already be active and conflicting with the GNOME settings manager.
Why would this be happening? And why only sometimes while most times there is no problem with the theme?