diff --git a/li.strolch.service/src/main/java/li/strolch/execution/SimpleDurationExecutionTimer.java b/li.strolch.service/src/main/java/li/strolch/execution/SimpleDurationExecutionTimer.java
index f4ff9f5e7..959540c3e 100644
--- a/li.strolch.service/src/main/java/li/strolch/execution/SimpleDurationExecutionTimer.java
+++ b/li.strolch.service/src/main/java/li/strolch/execution/SimpleDurationExecutionTimer.java
@@ -30,6 +30,8 @@ public class SimpleDurationExecutionTimer implements DelayedExecutionTimer {
 	@Override
 	public void destroy() {
 
+		this.simulationTasks.values().forEach(task -> task.cancel(false));
+
 		if (this.scheduledExecutorService != null) {
 			this.scheduledExecutorService.shutdown();
 			while (!this.scheduledExecutorService.isTerminated()) {