diff --git a/Machining/DemoBuildGeomOnlyMachiningProject.cs b/Machining/DemoBuildGeomOnlyMachiningProject.cs
index ef584be..f397c2c 100644
--- a/Machining/DemoBuildGeomOnlyMachiningProject.cs
+++ b/Machining/DemoBuildGeomOnlyMachiningProject.cs
@@ -96,6 +96,8 @@ public static class DemoBuildGeomOnlyMachiningProject
 		localProjectService.SaveProject();
 
 		machiningProject.Dispose();
+		//the service holds the play threads, the strip and the cut workpiece tree: dispose it before AppEnd
+		localProjectService.Dispose();
 		LocalApp.AppEnd();
 	}
 
diff --git a/Machining/DemoBuildMachiningProject.cs b/Machining/DemoBuildMachiningProject.cs
index 7bf12bc..ee7aa86 100644
--- a/Machining/DemoBuildMachiningProject.cs
+++ b/Machining/DemoBuildMachiningProject.cs
@@ -216,6 +216,8 @@ public static class DemoBuildMachiningProject
 		machiningProject.MakeXmlSourceToFile(projectPath);
 
 		machiningProject.Dispose();
+		//the service holds the play threads, the strip and the cut workpiece tree: dispose it before AppEnd
+		localProjectService.Dispose();
 		LocalApp.AppEnd();
 	}
 	#endregion
diff --git a/Machining/DemoUseMachiningProject.cs b/Machining/DemoUseMachiningProject.cs
index a906fb0..1f7c87a 100644
--- a/Machining/DemoUseMachiningProject.cs
+++ b/Machining/DemoUseMachiningProject.cs
@@ -85,6 +85,8 @@ public static class DemoUseMachiningProject
 		#region CleanupResources
 		Console.WriteLine($"Close Project: {projectPath}");
 		machiningProject.Dispose();
+		//the service holds the play threads, the strip and the cut workpiece tree: dispose it before AppEnd
+		localProjectService.Dispose();
 
 		LocalApp.AppEnd();