diff --git a/osal/FreeRTOS/FixedTimeslotTask.cpp b/osal/FreeRTOS/FixedTimeslotTask.cpp
index aed66349..3ec15a43 100644
--- a/osal/FreeRTOS/FixedTimeslotTask.cpp
+++ b/osal/FreeRTOS/FixedTimeslotTask.cpp
@@ -57,7 +57,7 @@ ReturnValue_t FixedTimeslotTask::startTask() {
 
 ReturnValue_t FixedTimeslotTask::addSlot(object_id_t componentId,
 		uint32_t slotTimeMs, int8_t executionStep) {
-	if (objectManager->get<ExecutableObjectIF>(componentId) != NULL) {
+	if (objectManager->get<ExecutableObjectIF>(componentId) != nullptr) {
 		if(slotTimeMs == 0) {
 			// TODO: FreeRTOS throws errors for zero values.
 			// maybe there is a better solution than this.
diff --git a/osal/linux/FixedTimeslotTask.cpp b/osal/linux/FixedTimeslotTask.cpp
index 04ceb4e6..2775e4f6 100644
--- a/osal/linux/FixedTimeslotTask.cpp
+++ b/osal/linux/FixedTimeslotTask.cpp
@@ -42,6 +42,7 @@ uint32_t FixedTimeslotTask::getPeriodMs() const {
 
 ReturnValue_t FixedTimeslotTask::addSlot(object_id_t componentId,
 		uint32_t slotTimeMs, int8_t executionStep) {
+<<<<<<< HEAD
 	if (!objectManager->get<ExecutableObjectIF>(componentId)) {
 		sif::error << "Component " << std::hex << componentId
 				   << " not found, not adding it to pst" << std::endl;
@@ -50,6 +51,16 @@ ReturnValue_t FixedTimeslotTask::addSlot(object_id_t componentId,
 
 	pst.addSlot(componentId, slotTimeMs, executionStep, this);
 	return HasReturnvaluesIF::RETURN_OK;
+=======
+	if (objectManager->get<ExecutableObjectIF>(componentId) != nullptr) {
+		pst.addSlot(componentId, slotTimeMs, executionStep, this);
+		return HasReturnvaluesIF::RETURN_OK;
+	}
+
+	error << "Component " << std::hex << componentId <<
+			" not found, not adding it to pst" << std::endl;
+	return HasReturnvaluesIF::RETURN_FAILED;
+>>>>>>> luz_FixedTimeslotTask_ExistenceCheck
 }
 
 ReturnValue_t FixedTimeslotTask::checkSequence() const {
diff --git a/osal/rtems/PollingTask.cpp b/osal/rtems/PollingTask.cpp
index c2dc629b..6b0c0fbd 100644
--- a/osal/rtems/PollingTask.cpp
+++ b/osal/rtems/PollingTask.cpp
@@ -66,10 +66,16 @@ ReturnValue_t PollingTask::startTask() {
 	}
 }
 
-ReturnValue_t PollingTask::addSlot(object_id_t componentId, uint32_t slotTimeMs,
-		int8_t executionStep) {
-	pst.addSlot(componentId, slotTimeMs, executionStep, this);
-	return HasReturnvaluesIF::RETURN_OK;
+ReturnValue_t PollingTask::addSlot(object_id_t componentId,
+		uint32_t slotTimeMs, int8_t executionStep) {
+	if (objectManager->get<ExecutableObjectIF>(componentId) != nullptr) {
+		pst.addSlot(componentId, slotTimeMs, executionStep, this);
+		return HasReturnvaluesIF::RETURN_OK;
+	}
+
+	sif::error << "Component " << std::hex << componentId <<
+			" not found, not adding it to pst" << std::endl;
+	return HasReturnvaluesIF::RETURN_FAILED;
 }
 
 uint32_t PollingTask::getPeriodMs() const {