Read this before you ask a question asking why you can't open your map in your modding programs: Explanations: Every program related to Halo 2 map modding that is in UMP besides Entity is old. They were created before the Halo modding community figured out how to do proper mods. Proper as in: How Bungie would have made it. As in, you can't tell that we did the mod, because it was done perfectly. Improper would be you could tell that we did it because it was so crudely done. Improper mods really damage the map file, if done to an extent the map won't load or even open in modding programs. Improper mod examples: Dothalo injects bitmaps wrong, it injects it in the wrong partition of the map. The map may load, but you will have serious troubles opening the mod in other programs later on. Insolence transfers tags wrong. It adds the data to the end of the map, like with Dothalo, you may be able to get the mod to load, but you will have serious trouble opening the map in other programs to mod later on. Also, if you transfer a tag your map from a different map with Insolence, then add chunks with any other program besides Entity, you will not be able to add anything else to a map with Insolence, since when you put two different types of improper mods together the hex is shifted all wrong, your map won't even load. Solution The only solution to these improper method problems is to use Entity for the start of your mod, to the end of it. Entity can do every single thing every other modding program can do put together (with maybe the exception of one...). If you use Entity to mod your maps, it will be done proper. Entity is a great program, easy and simple to use, easy to understand, and as able do everything, there is no reason not to use it, when there are reasons to use it.