FYI
It's great that the problem fixed itself, but for general reference or for others who may run into ii, the way to resolve a 'stuck or ghost share' is to remove it's entry in the registry key below and then log off and on or reboot. This problem is relatively rare, but comes up occasionally and does not always fix itself.
(Note that drive letter Q specifically is used by Office Click to Run and sometimes mysteriously appears for that reason, unlike your situation.)
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2]