By default, baloo_file should only autostart in KDE, but as it stands right now, it auto-starts in (at least) XFCE as well. The following line from baloo_file.desktop, which is placed in the system's XDG autostart dir is: OnlyShowIn=KDE;GNOME;Unity;XFCE This should be amended to just 'KDE'. Believe me, no one who runs XFCE, GNOME or Unity wants baloo_file to autostart on their systems.
*** This bug has been marked as a duplicate of bug 366561 ***