Current questions and answers regarding the map editor.

I believe this question has already been asked, but reading 129 pages isn't a quick task. Could you please advise? I want to edit a map created by the generator in Heroes of Might and Magic V: Tribes of the East. After closing the editor, even if I just open the map, it starts weighing 1KB and becomes unusable. What should I do? I have the Gold Edition. The version of Tribes of the East is 3.0. Also, is there a way to open maps that are already included in the game for editing? Thank you for your answers.