Locked Maps are Maps that are open on another user's computer, manually locked from the Maps list in a Solution, open in another browser, or the browser was closed while the Map was still open. They are marked by a Lock icon in the Status column on the Solution's Maps list. Select the lock to display the Locked By dialog. This contains the user name of the user locking the Map, and the date and time when it was locked.
If a Map is locked and the Locked By user has been deleted from the Organization, you cannot unlock the Map.