Current questions and answers regarding the map editor.

Hello everyone. Maybe someone can help me; I've encountered a problem. I was working on a large map, but before I finished it, I discovered that my computer was infected with a virus. I managed to save the map without any damage and copied it to a disk. I reinstalled Windows and then copied the unfinished map to the correct folder and continued working on it. However, after saving the finished map, I found that the map size had decreased to 1 KB, and I can no longer open it. I have a question about this: is there any way to finish the map and eventually play it?