If you turn on file sharing, select the hard drive icon, go to the finder File menu and select Sharing..., hopefully the item on the top "Where:" line is your hard drive name, not the dreaded Q250. Select (click the empty x box) Share this item and it's contents then unselect the x box. Does this make the phantom memory of the entire Q250 perhaps once having been designated as a shared folder go away? Don't know where all this is stored, but deep in the File Manager (Files: About the File Manager page 2- 18 ) is a notion of "blank access privileges" where files copied into an existing directory can be given the same access privileges of the root directory, including sharing attributes, perhaps an opportunity for cross contamination on your external drive where both the archived bits from the original Q250, and the later Q250 resanitized with 7.1.3 bits, intermingled before the 7.1.3 seed transfer to the 300MB partition.