I encountered weird issue. When I open map with landscape, 256 textures files are dynamically created and show up in Content Browser, same folder as umap file. These files aren’t saved as assets on disks and one cannot simply delete it 
Any idea what’s the cause? It seems to appear in 4.8.
Hey, I just ran into the exact same issue. It doesn’t seem to be problematic in game but it easily pollutes the content browser. Did you get any update on that?
After some digging around, I finally found what’s happening here.
I guess it’s a brand new option even though I can’t find it in the long list of release notes :
In your project settings, rendering, Generate landscape Real-time GI Data.
If you choose to use this option, the data used are baked whenever you use a landscape and displayed as a texture in the content browser so you can edit it but they are actually stored in the map file.
So I’d say you can uncheck this option or you’ll have to get along with it 
This is all guesses I made by trying and comparing different projects, versions etc. So don’t take it all for granted but I’m pretty sure that’s very close to how it is.
Works like a charm! Thanks a lot
Hey !
First of all, thank you for the useful answer @Xelareip. It served us well !
We’ve experienced the same issue lately and couldn’t find its reason (except that it was landscape related considering the number of texture files).
I’d like to add to this issue that whenever you try to duplicate the level file affected by the problem, UE4 crashes.
Same here. I have 1024 of these landscape associated textures that are only visible in the editor and not in Windows explorer.
I don’t mind them being there (I’ll put them into a subfolder later) but I’d also like to know how they appeared and what they are for (using UE4.10).
My ‘[x]Generate landscape Real-time GI Data’ is enabled but I don’t recall enabling it myself because I didn’t know what it was for.
Anyone know what the landscape GI thing is for? Are there any visual improvements with it on?