I created some custom maps (mostly by taking existing Skirmish maps, doing "Save As" to rename them something different, then modifying the map. However, when I load DK2 & go to Single Player -> Skirmish -> Select Map, most of the custom maps aren't displayed.

I *do* have "Skirmish Level" enabled under Level Variables.

What's really odd is that a few of my custom maps show, but most do not. Running Win10.

I figured out the answer to this:

The editor saves maps in:
Dungeon Keeper 2\dungeon_keeper_2_editor\dungeon_keeper_2_editor\maps

But for the maps to show up in game, they need to be saved to:
Dungeon Keeper 2\Data\editor\maps

Once the maps are in the Data\editor\maps folder, they show up in game for selection.