diff --git a/internal/pkg/category/category.go b/internal/pkg/category/category.go
index 7046b1d..09c9390 100644
--- a/internal/pkg/category/category.go
+++ b/internal/pkg/category/category.go
@@ -145,17 +145,20 @@ func createMissingCategories(piwigoApi piwigo.PiwigoCategoryApi, db datastore.Ca
 }
 
 func getParentId(category datastore.CategoryData, db datastore.CategoryProvider) (int, error) {
+	if category.Key == "" || category.Key == "." {
+		msg := fmt.Sprintf("Category with id %d has a invalid value in the keyfield!", category.CategoryId)
+		logrus.Warnf(msg)
+		return 0, errors.New(msg)
+	}
+
 	parentKey := filepath.Dir(category.Key)
-	if category.Name == parentKey {
+	if category.Name == parentKey || parentKey == "." || parentKey == "" {
 		logrus.Debugf("The category %s is a root category, there is no parent", category.Name)
 		return 0, nil
 	}
 
 	logrus.Debugf("Looking up parent with key %s", parentKey)
 	parentCategory, err := db.GetCategoryByKey(parentKey)
-	if err == datastore.ErrorRecordNotFound {
-		return 0, err
-	}
 	if err != nil {
 		return 0, err
 	}
diff --git a/internal/pkg/category/category_test.go b/internal/pkg/category/category_test.go
index 2b0f600..d1af168 100644
--- a/internal/pkg/category/category_test.go
+++ b/internal/pkg/category/category_test.go
@@ -74,8 +74,106 @@ func Test_updatePiwigoCategoriesFromServer_updates_a_category(t *testing.T) {
 	}
 }
 
+func Test_getParentId_returns_0_for_root_nodes(t *testing.T) {
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+
+	category := crateDbRootCategory()
+
+	dbmock := NewMockCategoryProvider(mockCtrl)
+	dbmock.EXPECT().GetCategoryByKey(gomock.Any()).Times(0)
+
+	parentId, err := getParentId(category, dbmock)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if parentId != 0 {
+		t.Errorf("Found parent id %d but expected 0", parentId)
+	}
+}
+
+func Test_getParentId_returns_error_if_parentkey_is_not_found(t *testing.T) {
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+
+	category := createDbSubCategory()
+
+	dbmock := NewMockCategoryProvider(mockCtrl)
+	dbmock.EXPECT().GetCategoryByKey(gomock.Any()).Return(datastore.CategoryData{}, datastore.ErrorRecordNotFound).Times(1)
+
+	parentId, err := getParentId(category, dbmock)
+	if err == nil {
+		t.Error("There should an error be returned if category key value is not valid!")
+	}
+	if parentId != 0 {
+		t.Errorf("Found parent id %d but expected 0", parentId)
+	}
+}
+
+func Test_getParentId_returns_error_if_key_invalid(t *testing.T) {
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+
+	category := crateDbRootCategory()
+	category.Key = "."
+
+	dbmock := NewMockCategoryProvider(mockCtrl)
+	dbmock.EXPECT().GetCategoryByKey(gomock.Any()).Times(0)
+
+	parentId, err := getParentId(category, dbmock)
+	if err == nil {
+		t.Error("There should an error be returned if category key value is not valid!")
+	}
+	if parentId != 0 {
+		t.Errorf("Found parent id %d but expected 0", parentId)
+	}
+}
+
+func Test_getParentId_finds_the_exptected_parent_id(t *testing.T) {
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+
+	parentCategory := crateDbRootCategory()
+	category := createDbSubCategory()
+
+	dbmock := NewMockCategoryProvider(mockCtrl)
+	dbmock.EXPECT().GetCategoryByKey("2019").Return(parentCategory, nil).Times(1)
+
+	parentId, err := getParentId(category, dbmock)
+	if err != nil {
+		t.Error(err)
+	}
+
+	if parentId != 1 {
+		t.Errorf("Found parent id %d but expected 1", parentId)
+	}
+}
+
+func crateDbRootCategory() datastore.CategoryData {
+	parentCategory := datastore.CategoryData{
+		PiwigoId:       1,
+		PiwigoParentId: 0,
+		CategoryId:     1,
+		Key:            "2019",
+		Name:           "2019",
+	}
+	return parentCategory
+}
+
+func createDbSubCategory() datastore.CategoryData {
+	category := datastore.CategoryData{
+		PiwigoId:       2,
+		PiwigoParentId: 0,
+		CategoryId:     2,
+		Key:            "2019/testalbumb",
+		Name:           "testalbumb",
+	}
+	return category
+}
+
 func createDbCategoriesFrom(categories map[string]*piwigo.PiwigoCategory) []datastore.CategoryData {
-	dbCategories := []datastore.CategoryData{}
+	var dbCategories []datastore.CategoryData
 	for _, cat := range categories {
 		dbCat := datastore.CategoryData{
 			PiwigoId:       cat.Id,