diff --git a/smartmontools/ChangeLog b/smartmontools/ChangeLog
index 9d46f94047fb4420c33968eaa9811f0bafa62662..0612a64f06882f45b671019f86c56f5dc2a7e22e 100644
--- a/smartmontools/ChangeLog
+++ b/smartmontools/ChangeLog
@@ -1,5 +1,10 @@
 $Id$
 
+2022-08-06  themylogin  <themylogin@gmail.com>
+
+	smartd.cpp: Also prevent systemd unit startup timeout in
+	`CheckDevicesOnce` (GH pull/141).
+
 2022-08-06  Christian Franke  <franke@computer.org>
 
 	drivedb.h:
diff --git a/smartmontools/smartd.cpp b/smartmontools/smartd.cpp
index 2b3c81c188cbd4c0b09c8eace1df6f6c2a764e97..0e0503fb6da37ff073567548cce30f4ed7395f28 100644
--- a/smartmontools/smartd.cpp
+++ b/smartmontools/smartd.cpp
@@ -3956,6 +3956,9 @@ static void CheckDevicesOnce(const dev_config_vector & configs, dev_state_vector
       SCSICheckDevice(cfg, state, dev->to_scsi(), allow_selftests);
     else if (dev->is_nvme())
       NVMeCheckDevice(cfg, state, dev->to_nvme());
+
+    // Prevent systemd unit startup timeout when checking many devices on startup
+    notify_extend_timeout();
   }
 
   do_disable_standby_check(configs, states);