Ser9K
Auto-translated
Anton A.A.
There is only one hope. Go to Heroes of Might and Magic V - Tribes of the East\Editor\H5MMods and find the folder that has the same name as your map. Since .h5m is an archive, the game (or rather, the editor) unpacks it for convenience. The map is stored in unpacked form there. Check the two files: GroundTerrain.bin and map.xdb. The first one is about a megabyte in size, and the second is 500 kilobytes. If they are both 1 KB, then you will have to start from scratch. If not, there is a chance to pack this folder and save the map.
There is only one hope. Go to Heroes of Might and Magic V - Tribes of the East\Editor\H5MMods and find the folder that has the same name as your map. Since .h5m is an archive, the game (or rather, the editor) unpacks it for convenience. The map is stored in unpacked form there. Check the two files: GroundTerrain.bin and map.xdb. The first one is about a megabyte in size, and the second is 500 kilobytes. If they are both 1 KB, then you will have to start from scratch. If not, there is a chance to pack this folder and save the map.