diff --git a/src/cli/action_convert.cpp b/src/cli/action_convert.cpp
index 3e2179b..60836b8 100644
--- a/src/cli/action_convert.cpp
+++ b/src/cli/action_convert.cpp
@@ -618,5 +618,5 @@ static const vlChar* get_last_vtflib_error() {
 		return error + 7;
 	}
 
-	return "N/D";
+	return "Unknown error";
 }