This is likely one of two things:
- One person is using the Mapmaker, and another person is making changes in the Space (e.g., adds an object or adds/changes the Space password). When the person in the Mapmaker saves, any changes that were made in the Space are overridden (e.g., the newly added objects disappear or the Space password doesn't save).
- More than one person is using the Mapmaker. When one of them selects Save, the changes by the other person are overridden.