diff --git a/src/mfm_dup.cpp b/src/mfm_dup.cpp
index 73ae8cdd..c3c9b630 100644
--- a/src/mfm_dup.cpp
+++ b/src/mfm_dup.cpp
@@ -47,7 +47,8 @@ mfm::dup(const Opts::Dup &opts_)
         }
       else
         {
-
+          //throw std::runtime_error("invalid file type");
+          fmt::println("invalid file type: {}",path);
         }
     }
 }