Did everything that has been posted in this topic and still got this message, found this in the engine source
bool bNaniteDisabledButNoFallbackMeshes = !UseNanite(Scene->GetShaderPlatform()) && !AreNaniteFallbackMeshesEnabledForPlatform(Scene->GetShaderPlatform());
// ...
if (bNaniteDisabledButNoFallbackMeshes)
{
static const FText Message = NSLOCTEXT("Renderer", "NaniteDisabledButNoFallbackMeshes", "Nanite is disabled but fallback meshes were stripped during cooking for this platform due to project settings. Meshes might not render correctly.");
Writer.DrawLine(Message);
}
What finally freed me from this message was enabling “Generate Nanite Fallback Meshes” in Project Settings → Platforms → Windows (as I’m developing on Windows).
As far as I know, this option does absolutely nothing on meshes that don’t have Nanite enabled - am I correct?
It might be helpful to alter this message to something like this
"Nanite is disabled but fallback meshes were stripped during cooking for this platform due to project settings (relevant property: bGenerateNaniteFallbackMeshes). Meshes might not render correctly."