Why do I have two instances of the same partition in Nautilus?

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http://askubuntu.com – Don't quite recall when this started behaving like this but Gnome's Nautilus has been reporting a sort of 'ghost' partition that's labeled the same as the regular one: The partition resides on a RAID1. Clicking on the 'ghost' partition provides: mount: /dev/md127p1 already mounted or /media/Music_Library busy mount: according to mtab, /dev/md127p1 is already mounted on /media/Music_Library My fstab: # / was on /dev/sdh2 during installation UUID=15bb606e-54af-4fa3-8341-12824a404dae / ext4 errors=remount-ro 0 1 # /home was on /dev/sdh3 during installation (HowTos)