diff --git a/fail-monitor/Makefile.am b/fail-monitor/Makefile.am
index 6c5c5b2..61fde80 100644
--- a/fail-monitor/Makefile.am
+++ b/fail-monitor/Makefile.am
@@ -5,6 +5,7 @@
 	phosphor-unit-failure-monitor
 
 phosphor_unit_failure_monitor_SOURCES = \
+	argument.cpp \
 	main.cpp \
 	monitor.cpp