diff --git a/jf-buffer-writer/src/main.cpp b/jf-buffer-writer/src/main.cpp
index 81c7705..c8eb032 100644
--- a/jf-buffer-writer/src/main.cpp
+++ b/jf-buffer-writer/src/main.cpp
@@ -16,7 +16,7 @@ using namespace BufferUtils;
 
 int main (int argc, char *argv[]) {
 
-    if (argc != 2) {
+    if (argc != 3) {
         cout << endl;
         cout << "Usage: jf_buffer_writer [detector_json_filename] [module_id]";
         cout << endl;