diff --git a/code/nel/tools/3d/zone_ig_lighter/zone_ig_lighter.cpp b/code/nel/tools/3d/zone_ig_lighter/zone_ig_lighter.cpp
index 0010d5179..a6636730f 100644
--- a/code/nel/tools/3d/zone_ig_lighter/zone_ig_lighter.cpp
+++ b/code/nel/tools/3d/zone_ig_lighter/zone_ig_lighter.cpp
@@ -410,6 +410,12 @@ int main(int argc, char* argv[])
 						if(group->getInstance(instance).DontCastShadow || group->getInstance(instance).DontCastShadowForExterior)
 							continue;
 
+						if (toLower (CFile::getExtension (name)) == "pacs_prim")
+						{
+							nlwarning("EXPORT BUG: Can't read %s (not a shape), should not be part of .ig!", name.c_str());
+							continue;
+						}
+
 						// Add a .shape at the end ?
 						if (!name.empty())
 						{