Азгалор
I ran into a problem today. I was working on my map, saved it so I could finish it later, and now when I open it again, it gives me this error (The file may be corrupted file version unsupported or you are trying to load the map from outside the[ Game installation
Try opening the map again — maybe only the GroundTerrain/UndergroundTerrain.bin got corrupted (I've had cases where a map's landscape broke, and instead of ground, objects were standing on empty space). To fix this, you need to create a new map with the same settings as yours, then go into its files (approximate path below) and copy the GroundTerrain/UndergroundTerrain.bin files from it into your map (UndergroundTerrain won't be in the folder if you don't have the underground map enabled).
Another option, if that doesn't work: go into the map files (if you have Windows 10, it should be at this path (yours may differ — better to go to Users and search for H5MMods): C:\Users\Administrator\AppData\Local\VirtualStore\ Program Files (x86)\Nival Interactive\Heroes of Might and Magic V - Tribes of the East\Editor\H5MMods, then the folder with your map's name, Maps, SingleMission/Multiplayer, then the folder named the same as you named the map in the creation settings, open the map.xdb file (the extension may not show if you don't have the corresponding setting enabled on your computer/laptop) and scroll through it. If the file contains various objects from the map, i.e. after <objects> there's something like <Item href="#n:inline(AdvMapTown)" id="item_1507AA89-FE7D-4E5E-9970-013145DC272E">, then close the file, copy and paste it to your desktop, delete the map, then create it again, and afterwards copy and paste the map.xdb file from the desktop into the root of the new map the same way, then reload the new map and your placed objects will appear on it. You could take a risk and make a copy of the landscapes (if you've already worked on them), but again — at your own risk. The landscape can easily break the map.
Oh, and yes — it's possible the problem was caused by your map being named with the Russian keyboard layout. But I don't know for sure, because I've never named maps with Russian letters and I've never had this problem. The editor specialists here will give you a definitive answer on that.