diff --git a/manager/scheduler/scheduler.go b/manager/scheduler/scheduler.go
index 9ee0b9e5c9..9e708ed1b6 100644
--- a/manager/scheduler/scheduler.go
+++ b/manager/scheduler/scheduler.go
@@ -702,9 +702,20 @@ func (s *Scheduler) scheduleNTasksOnNodes(ctx context.Context, n int, taskGroup
 	return tasksScheduled
 }
 
+// noSuitableNode checks unassigned tasks and make sure they have an existing service in the store before
+// updating the task status and adding it back to: schedulingDecisions, unassignedTasks and allTasks
 func (s *Scheduler) noSuitableNode(ctx context.Context, taskGroup map[string]*api.Task, schedulingDecisions map[string]schedulingDecision) {
 	explanation := s.pipeline.Explain()
 	for _, t := range taskGroup {
+		var service *api.Service
+		s.store.View(func(tx store.ReadTx) {
+			service = store.GetService(tx, t.ServiceID)
+		})
+		if service == nil {
+			log.G(ctx).WithField("task.id", t.ID).Debug("removing task from the scheduler")
+			continue
+		}
+
 		log.G(ctx).WithField("task.id", t.ID).Debug("no suitable node available for task")
 
 		newT := *t
diff --git a/manager/scheduler/scheduler_test.go b/manager/scheduler/scheduler_test.go
index 2126e70397..d387dc4a01 100644
--- a/manager/scheduler/scheduler_test.go
+++ b/manager/scheduler/scheduler_test.go
@@ -1114,6 +1114,7 @@ func TestSchedulerNoReadyNodes(t *testing.T) {
 	ctx := context.Background()
 	initialTask := &api.Task{
 		ID:           "id1",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name1",
@@ -1128,7 +1129,8 @@ func TestSchedulerNoReadyNodes(t *testing.T) {
 	defer s.Close()
 
 	err := s.Update(func(tx store.Tx) error {
-		// Add initial task
+		// Add initial service and task
+		assert.NoError(t, store.CreateService(tx, &api.Service{ID: "serviceID1"}))
 		assert.NoError(t, store.CreateTask(tx, initialTask))
 		return nil
 	})
@@ -1536,6 +1538,7 @@ func TestSchedulerResourceConstraint(t *testing.T) {
 
 	initialTask := &api.Task{
 		ID:           "id1",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -1559,12 +1562,17 @@ func TestSchedulerResourceConstraint(t *testing.T) {
 		},
 	}
 
+	initialService := &api.Service{
+		ID: "serviceID1",
+	}
+
 	s := store.NewMemoryStore(nil)
 	assert.NotNil(t, s)
 	defer s.Close()
 
 	err := s.Update(func(tx store.Tx) error {
-		// Add initial node and task
+		// Add initial node, service and task
+		assert.NoError(t, store.CreateService(tx, initialService))
 		assert.NoError(t, store.CreateTask(tx, initialTask))
 		assert.NoError(t, store.CreateNode(tx, underprovisionedNode))
 		assert.NoError(t, store.CreateNode(tx, nonready1))
@@ -1788,6 +1796,7 @@ func TestSchedulerResourceConstraintDeadTask(t *testing.T) {
 	bigTask1 := &api.Task{
 		DesiredState: api.TaskStateRunning,
 		ID:           "id1",
+		ServiceID:    "serviceID1",
 		Spec: api.TaskSpec{
 			Resources: &api.ResourceRequirements{
 				Reservations: &api.Resources{
@@ -1809,12 +1818,17 @@ func TestSchedulerResourceConstraintDeadTask(t *testing.T) {
 	bigTask2 := bigTask1.Copy()
 	bigTask2.ID = "id2"
 
+	bigService := &api.Service{
+		ID: "serviceID1",
+	}
+
 	s := store.NewMemoryStore(nil)
 	assert.NotNil(t, s)
 	defer s.Close()
 
 	err := s.Update(func(tx store.Tx) error {
-		// Add initial node and task
+		// Add initial node, service and task
+		assert.NoError(t, store.CreateService(tx, bigService))
 		assert.NoError(t, store.CreateNode(tx, node))
 		assert.NoError(t, store.CreateTask(tx, bigTask1))
 		return nil
@@ -1951,6 +1965,7 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	// task1 - has a node it can run on
 	task1 := &api.Task{
 		ID:           "id1",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name1",
@@ -1973,6 +1988,7 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	// task2 - has no node it can run on
 	task2 := &api.Task{
 		ID:           "id2",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name2",
@@ -1995,6 +2011,7 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	// task3 - no platform constraints, should run on any node
 	task3 := &api.Task{
 		ID:           "id3",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name3",
@@ -2007,6 +2024,7 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	// task4 - only OS constraint, is runnable on any linux node
 	task4 := &api.Task{
 		ID:           "id4",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name4",
@@ -2029,6 +2047,7 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	// task5 - supported on multiple platforms
 	task5 := &api.Task{
 		ID:           "id5",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		ServiceAnnotations: api.Annotations{
 			Name: "name5",
@@ -2103,12 +2122,16 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 		Description: &api.NodeDescription{},
 	}
 
+	service1 := &api.Service{
+		ID: "serviceID1",
+	}
 	s := store.NewMemoryStore(nil)
 	assert.NotNil(t, s)
 	defer s.Close()
 
 	err := s.Update(func(tx store.Tx) error {
-		// Add initial task and nodes to the store
+		// Add initial task, service and nodes to the store
+		assert.NoError(t, store.CreateService(tx, service1))
 		assert.NoError(t, store.CreateTask(tx, task1))
 		assert.NoError(t, store.CreateNode(tx, node1))
 		assert.NoError(t, store.CreateNode(tx, node2))
@@ -2168,6 +2191,86 @@ func TestSchedulerCompatiblePlatform(t *testing.T) {
 	assert.Regexp(t, assignment4.NodeID, "(node1|node2)")
 }
 
+// TestSchedulerUnassignedMap tests that unassigned tasks are deleted from unassignedTasks when the service is removed
+func TestSchedulerUnassignedMap(t *testing.T) {
+	ctx := context.Background()
+	// create a service and a task with OS constraint that is not met
+	task1 := &api.Task{
+		ID:           "id1",
+		ServiceID:    "serviceID1",
+		DesiredState: api.TaskStateRunning,
+		ServiceAnnotations: api.Annotations{
+			Name: "name1",
+		},
+		Status: api.TaskStatus{
+			State: api.TaskStatePending,
+		},
+		Spec: api.TaskSpec{
+			Placement: &api.Placement{
+				Platforms: []*api.Platform{
+					{
+						Architecture: "amd64",
+						OS:           "windows",
+					},
+				},
+			},
+		},
+	}
+
+	node1 := &api.Node{
+		ID: "node1",
+		Spec: api.NodeSpec{
+			Annotations: api.Annotations{
+				Name: "node1",
+			},
+		},
+		Status: api.NodeStatus{
+			State: api.NodeStatus_READY,
+		},
+		Description: &api.NodeDescription{
+			Platform: &api.Platform{
+				Architecture: "x86_64",
+				OS:           "linux",
+			},
+		},
+	}
+
+	service1 := &api.Service{
+		ID: "serviceID1",
+	}
+
+	s := store.NewMemoryStore(nil)
+	assert.NotNil(t, s)
+	defer s.Close()
+
+	err := s.Update(func(tx store.Tx) error {
+		// Add initial task, service and nodes to the store
+		assert.NoError(t, store.CreateService(tx, service1))
+		assert.NoError(t, store.CreateTask(tx, task1))
+		assert.NoError(t, store.CreateNode(tx, node1))
+		return nil
+	})
+	assert.NoError(t, err)
+
+	scheduler := New(s)
+	scheduler.unassignedTasks["id1"] = task1
+
+	scheduler.tick(ctx)
+	// task1 is in the unassigned map
+	assert.Contains(t, scheduler.unassignedTasks, task1.ID)
+
+	// delete the service of an unassigned task
+	err = s.Update(func(tx store.Tx) error {
+		assert.NoError(t, store.DeleteService(tx, service1.ID))
+		return nil
+	})
+	assert.NoError(t, err)
+
+	scheduler.tick(ctx)
+	// task1 is removed from the unassigned map
+	assert.NotContains(t, scheduler.unassignedTasks, task1.ID)
+}
+
 func TestPreassignedTasks(t *testing.T) {
 	ctx := context.Background()
 	initialNodeSet := []*api.Node{
@@ -2523,6 +2626,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task0: bind mount
 	t0 := &api.Task{
 		ID:           "task0_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2548,6 +2652,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task1: vol plugin1
 	t1 := &api.Task{
 		ID:           "task1_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2574,6 +2679,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task2: vol plugin1, vol plugin2
 	t2 := &api.Task{
 		ID:           "task2_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2606,6 +2712,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task3: vol plugin1, network plugin1
 	t3 := &api.Task{
 		ID:           "task3_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Networks: []*api.NetworkAttachment{
 			{
@@ -2646,6 +2753,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task4: log plugin1
 	t4 := &api.Task{
 		ID:           "task4_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2663,6 +2771,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// Task5: log plugin1
 	t5 := &api.Task{
 		ID:           "task5_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2681,6 +2790,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// no logging
 	t6 := &api.Task{
 		ID:           "task6_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2699,6 +2809,7 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 	// log driver with no name
 	t7 := &api.Task{
 		ID:           "task7_ID",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -2718,12 +2829,16 @@ func TestSchedulerPluginConstraint(t *testing.T) {
 		},
 	}
 
+	s1 := &api.Service{
+		ID: "serviceID1",
+	}
 	s := store.NewMemoryStore(nil)
 	assert.NotNil(t, s)
 	defer s.Close()
 
-	// Add initial node and task
+	// Add initial node, service and task
 	err := s.Update(func(tx store.Tx) error {
+		assert.NoError(t, store.CreateService(tx, s1))
 		assert.NoError(t, store.CreateTask(tx, t1))
 		assert.NoError(t, store.CreateNode(tx, n1))
 		return nil
@@ -3014,6 +3129,7 @@ func TestSchedulerHostPort(t *testing.T) {
 
 	task1 := &api.Task{
 		ID:           "id1",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -3038,6 +3154,7 @@ func TestSchedulerHostPort(t *testing.T) {
 	}
 	task2 := &api.Task{
 		ID:           "id2",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -3062,6 +3179,7 @@ func TestSchedulerHostPort(t *testing.T) {
 	}
 	task3 := &api.Task{
 		ID:           "id3",
+		ServiceID:    "serviceID1",
 		DesiredState: api.TaskStateRunning,
 		Spec: api.TaskSpec{
 			Runtime: &api.TaskSpec_Container{
@@ -3090,12 +3208,17 @@ func TestSchedulerHostPort(t *testing.T) {
 		},
 	}
 
+	service1 := &api.Service{
+		ID: "serviceID1",
+	}
+
 	s := store.NewMemoryStore(nil)
 	assert.NotNil(t, s)
 	defer s.Close()
 
 	err := s.Update(func(tx store.Tx) error {
-		// Add initial node and task
+		// Add initial node, service and task
+		assert.NoError(t, store.CreateService(tx, service1))
 		assert.NoError(t, store.CreateTask(tx, task1))
 		assert.NoError(t, store.CreateTask(tx, task2))
 		return nil