Adding levels to the persistent level

I have a persistent level; streaming and everything works fine.

I have some sub-levels but I cannot add anymore. I can’t find any documentation about the feature with regards to its specifications (I’m aware of this (World Composition User Guide | Unreal Engine Documentation) and haven’t been able to find the proper .h .cpp files in the engine which handle adding sub levels to a persistent level (where is this?).

I place the level into the folder but it does not get added to the persistent level. I also try to drag and drop the level into the Levels window, and while it gives me the green checkmark, it will not add.

Video (- YouTube).

Are only 13 sub levels allowed?

I guess if anyone knows where this is handled in the source code that would be the most useful thing.


This is what my world composition looks like. 11 in the upper left then going right its 12 then 13, I removed 14 and now cannot put it back in. 21, 22, and 23 are missing while you can see 24 on the end of the second row. All of row 3 and 4 are there.


Also here is a view of some of the levels loaded in the editor.


I found out something else weird. Some of the maps show their size to be 15.999 EB


Most of the maps show their normal file size in the editor but the ones I can’t add are listed with 15.999 EB. They also have a modified date of 1/2/01. Seems like some zero values and maybe the size wrapped around for the map size (16 EB is about the size of the number of bytes counted by an unsigned 64 bit integer).

Some kind of corruption perhaps? I have tried to duplicate the maps and place them back into the folder and they still do not add themselves.