Ubuntu Installation :: Duplicate Drives In "Places" - Error "mount: /dev/sdd1 Already Mounted Or /media/Data Busy Mount: According To Mtab, /dev/sdd1 Is Already Mounted On /media/Data"

Just moved to Ubuntu from XP. Whole process has gone very smoothly, but left with a small problem (i.e. it isn't actually affecting usability) that I don't seem to be able to fix and can't find on forums/internet. I also have a problem with the Floppy drive, but I've seen that problem elsewhere in the forums.

It's a dual boot system with both NTFS and Ext4 drives. All are visible and fully accessible. I decided to convert one of the NTFS drive to Ext4. That appeared to be successful and was successfully remounted as an Ext4 drive. The drive label is "Data". I did have a bit of a problem getting it remounted so that I could see/use it under my log-in as opposed to just under root. It's at this point I think that I did something to create the problem.

I now have two entries for "Data" in drop down menu for Places. The true one is shown as a standard hard drive icon, but the false one is shown as a different icon - possibly an external drive icon (note that the floppy drive is also showing as the same icon and I can't access that, but I've seen that's a problem elsewhere in the forums).

I can write and read to the true "Data" hard drive. If I click on the other false "Data" icon, I get the message "mount: /dev/sdd1 already mounted or /media/Data busy mount: according to mtab, /dev/sdd1 is already mounted on /media/Data". If unmount the true drive and try to mount the false drive, the system mounts the true drive instead. If I log into nautilus as root, neither the false data drive or the floppy appear in the left hand panel.