diff --git a/app/tools/checker_worker.py b/app/tools/checker_worker.py
index 03ad400f..9f8154ea 100644
--- a/app/tools/checker_worker.py
+++ b/app/tools/checker_worker.py
@@ -22,6 +22,7 @@ def main(serv, port):
 	port = str(port)
 	firstrun = True
 	currentstat = []
+	oldstat = []
 	readstats = ""
 	killer = GracefulKiller()
 	old_stat_service = ""
@@ -101,4 +102,4 @@ if __name__ == "__main__":
 		try:
 			main(args.IP, args.port)
 		except KeyboardInterrupt:
-			pass
\ No newline at end of file
+			pass