Uasset files namely. Like we have an application that we build once and distribute, and then supply new content packages without users needing to get an update of the original application. So, for example, we tried having a .pak file that contained a 3d model and materials + textures for it. Unreal (both in editor and builds) can read the pak file, see its contents, can mount it, but then when pulling content from the PAK it fails every time saying the files don’t exist. Seems to be an issue with Unreal.