diff --git a/core/lib/Drupal/Core/Config/ConfigInstaller.php b/core/lib/Drupal/Core/Config/ConfigInstaller.php
index d702b26..9d0f81d 100644
--- a/core/lib/Drupal/Core/Config/ConfigInstaller.php
+++ b/core/lib/Drupal/Core/Config/ConfigInstaller.php
@@ -9,6 +9,7 @@
 
 use Drupal\Component\Utility\Unicode;
 use Drupal\Core\Config\Entity\ConfigDependencyManager;
+use Drupal\Core\Entity\EntityTypeInterface;
 use Drupal\Core\Site\Settings;
 use Psr\Log\LoggerInterface;
 use Symfony\Component\EventDispatcher\EventDispatcherInterface;
@@ -71,8 +72,6 @@ class ConfigInstaller implements ConfigInstallerInterface {
    */
   protected $isSyncing = FALSE;
 
-  protected $isInstalling = FALSE;
-
   /**
    * Constructs the configuration installer.
    *
@@ -102,7 +101,6 @@ public function __construct(ConfigFactoryInterface $config_factory, StorageInter
    * {@inheritdoc}
    */
   public function installDefaultConfig($type, $name) {
-    $this->isInstalling = TRUE;
     $extension_path = drupal_get_path($type, $name);
     // Refresh the schema cache if the extension provides configuration schema
     // or is a theme.
@@ -119,9 +117,9 @@ public function installDefaultConfig($type, $name) {
       }
       else {
         // The configuration importer sets the source storage on the config
-        // installer. The configuration importer handles all of the configuration
-        // entity imports. We only need to ensure that simple configuration is
-        // created when the extension is installed.
+        // installer. The configuration importer handles all of the
+        // configuration entity imports. We only need to ensure that simple
+        // configuration is created when the extension is installed.
         $prefix = $name;
       }
 
@@ -145,15 +143,17 @@ public function installDefaultConfig($type, $name) {
       // Install any optional configuration entities whose type this extension
       // provides. This searches all the installed modules config/optional
       // directories.
-      // @todo consider optimising this by checking if the extension provides
-      //   any configuration entities.
-      $storage = new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_OPTIONAL_DIRECTORY, StorageInterface::DEFAULT_COLLECTION, FALSE);
-      $this->setSourceStorage($storage);
-      $this->installOptionalConfig($name);
+      $provides_config_entity_type = array_reduce($this->configManager->getEntityManager()->getDefinitions(), function ($return, EntityTypeInterface $entity_type) use ($name) {
+        return $return ?: $entity_type->getProvider() && $entity_type->getConfigPrefix();
+      }, FALSE);
+      if ($provides_config_entity_type) {
+        $storage = new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_OPTIONAL_DIRECTORY, StorageInterface::DEFAULT_COLLECTION, FALSE);
+        $this->setSourceStorage($storage);
+        $this->installOptionalConfig($name);
+      }
     }
 
     // Reset all the static caches and list caches.
-    $this->isInstalling = FALSE;
     $this->configFactory->reset();
     $this->resetSourceStorage();
   }
@@ -308,26 +308,18 @@ protected function createConfiguration($collection, array $data) {
    * {@inheritdoc}
    */
   public function installCollectionDefaultConfig($collection) {
-    // We're in the middle of a config install any collections will be picked up
-    // later?
-    // @todo is this really correct.
-    if ($this->isInstalling) {
-      return;
-    }
-    $this->setSourceStorage(new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_INSTALL_DIRECTORY, $collection, drupal_installation_attempted()));
-    $config_to_install = $this->getSourceStorage($collection)->listAll();
-    // @todo is this right?
+    $storage = new ExtensionInstallStorage($this->getActiveStorages(StorageInterface::DEFAULT_COLLECTION), InstallStorage::CONFIG_INSTALL_DIRECTORY, $collection, drupal_installation_attempted());
+    // Only install configuration for enabled extensions.
     $enabled_extensions = $this->getEnabledExtensions();
-    $config_to_install = array_filter($config_to_install, function ($config_name) use ($enabled_extensions) {
+    $config_to_install = array_filter($storage->listAll(), function ($config_name) use ($enabled_extensions) {
       $provider = Unicode::substr($config_name, 0, strpos($config_name, '.'));
       return in_array($provider, $enabled_extensions);
     });
     if (!empty($config_to_install)) {
-      $this->createConfiguration($collection, $this->getSourceStorage($collection)->readMultiple($config_to_install));
+      $this->createConfiguration($collection, $storage->readMultiple($config_to_install));
       // Reset all the static caches and list caches.
       $this->configFactory->reset();
     }
-    $this->resetSourceStorage();
   }
 
   /**