diff --git a/source/logic/main.py b/source/logic/main.py
index 52eea7f..1f89705 100644
--- a/source/logic/main.py
+++ b/source/logic/main.py
@@ -206,7 +206,7 @@ def main():
 						### get old state and examine whether the check shall be executed
 						rows1 = sqlite_query_get(
 							database_path,
-							"SELECT MIN(timestamp) FROM results WHERE (check_name = :check_name) AND (notification_sent = TRUE);",
+							"SELECT MAX(timestamp) FROM results WHERE (check_name = :check_name) AND (notification_sent = TRUE);",
 							{
 								"check_name": check_data["name"],
 							}
@@ -378,7 +378,7 @@ def main():
 										)
 									)
 				
-				if (not _os.exists(args.mutex_path)):
+				if (not _os.path.exists(args.mutex_path)):
 					pass
 				else:
 					_os.remove(args.mutex_path)