diff --git a/core/core.services.yml b/core/core.services.yml
index 1c898cb..9a5e8bf 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -290,7 +290,7 @@ services:
     arguments: ['%container.modules%', '@cache.bootstrap']
   module_installer:
     class: Drupal\Core\Extension\ModuleInstaller
-    arguments: ['@module_handler', '@kernel']
+    arguments: ['@module_handler', '@kernel', '@entity.manager']
   theme_handler:
     class: Drupal\Core\Extension\ThemeHandler
     arguments: ['@config.factory', '@module_handler', '@state', '@info_parser', '@logger.channel.default', '@asset.css.collection_optimizer', '@config.installer', '@config.manager', '@router.builder_indicator']
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstaller.php b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
index f5e3c2d..4d8578e 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstaller.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstaller.php
@@ -10,6 +10,7 @@
 use Drupal\Component\Serialization\Yaml;
 use Drupal\Core\Cache\CacheBackendInterface;
 use Drupal\Core\DrupalKernelInterface;
+use Drupal\Core\Entity\EntityManagerInterface;
 
 /**
  * Default implementation of the module installer.
@@ -27,12 +28,24 @@ class ModuleInstaller implements ModuleInstallerInterface {
   protected $moduleHandler;
 
   /**
+   * @var \Drupal\Core\Entity\EntityManagerInterface
+   */
+  protected $entityManager;
+
+  /**
+   * Modules that can be uninstalled.
+   * @var array
+   */
+  protected $uninstallValidated;
+
+  /**
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler.
    */
-  public function __construct(ModuleHandlerInterface $module_handler, DrupalKernelInterface $kernel) {
+  public function __construct(ModuleHandlerInterface $module_handler, DrupalKernelInterface $kernel, EntityManagerInterface $entity_manager) {
     $this->moduleHandler = $module_handler;
     $this->kernel = $kernel;
+    $this->entityManager = $entity_manager;
   }
 
   /**
@@ -246,6 +259,7 @@ public function install(array $module_list, $enable_dependencies = TRUE) {
    * {@inheritdoc}
    */
   public function uninstall(array $module_list, $uninstall_dependents = TRUE) {
+    $this->validateUninstall($module_list);
     // Get all module data so we can find dependencies and sort.
     $module_data = system_rebuild_module_data();
     $module_list = $module_list ? array_combine($module_list, $module_list) : array();
@@ -436,4 +450,18 @@ protected function updateKernel($module_filenames) {
     $this->moduleHandler = $container->get('module_handler');
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function validateUninstall($module_list) {
+    foreach ($this->entityManager->getDefinitions() as $type => $entity_type) {
+      $entity_type->getProvider();
+      // @todo: perform an entity query to see if any entities of this type
+      // exist. If they do and the entity type provider is in $module_list,
+      // remove it from $module_list and drupal_set_message an explanation of
+      // why the module cannot be uninstalled.
+      // Update $this->uninstallValidated with modules that can be removed.
+      // Refer to $this->uninstallValidated to speed this up.
+    }
+  }
 }
diff --git a/core/lib/Drupal/Core/Extension/ModuleInstallerInterface.php b/core/lib/Drupal/Core/Extension/ModuleInstallerInterface.php
index 246af4b..d2d5409 100644
--- a/core/lib/Drupal/Core/Extension/ModuleInstallerInterface.php
+++ b/core/lib/Drupal/Core/Extension/ModuleInstallerInterface.php
@@ -58,5 +58,13 @@ public function install(array $module_list, $enable_dependencies = TRUE);
    */
   public function uninstall(array $module_list, $uninstall_dependents = TRUE);
 
+  /**
+   * Determines which modules can be uninstalled.
+   *
+   * @param array $module_list
+   *   The modules to uninstall.
+   */
+  public function validateUninstall($module_list);
+
 }