My son wanted to play Minecraft on the PC instead of the xbox360, so I moved a few worlds over. One was only partially successful. We used your Horizon 188.8.131.52 method, but the world is defective.
In this world, when we load it on the PC, it looks like the main xbox map was literally dropped into another PC world–the mountains on this world are sheared right through with laser precision. The biomes do not match where the shears occur, i.e. desert biomes immediately next to forest with no blending.
One of the structures we built, a sizeable castle, is only about 20% there, the rest “sheared away,” covered by ocean. In fact, the bulk of the structures and terraforming are absent (now underwater in the PC version).
Closer inspection of the regions show that r.0.0.mca was associated with an entirely different world seed. I manually edited the seed back to the proper one, but our structures are still missing in game.
Looking at the map with UME (Universal Minecraft Editor) shows that the original map and all the structures are still there.
The section r.0.0.mca is the lower right hand quarter of the map (attached). In the PC game, this entire quadrant is sheared and replaced with ocean. On the original xbox360 game, all the structures are there and accessible.
I’ve tried using other tools like MCEdit, MCC Tool Chest and the Minecraft Map Converter, all with no success.
My son is very excited about playing on the PC using the structures we built in the xbox360 version of Minecraft: a huge farm, a huge castle, a pirate ship and a huge battle arena, all of which were constructed painstakingly block by block on the 360.
Your help with fixing this issue would be greatly appreciated.