I remap my Music and Videos locations (by right-click, Properties, Location tab) to a different (slow/spinning disk) drive and those do not show up when I try to select a move-on-complete location for the first time in the session. When I dismiss the dialog and try again, all the missing re-mapped locations appear. I am guessing it is because the dialog is no longer waiting for them to resolve (and therefore assume they do not exist) before displaying the list -- while in the background it is properly resolved/cached for subsequent tries.