diff --git a/core/--cached b/core/--cached
new file mode 100644
index 0000000..e69de29
diff --git a/core/includes/config.inc b/core/includes/config.inc
index 0011533..11000b6 100644
--- a/core/includes/config.inc
+++ b/core/includes/config.inc
@@ -195,6 +195,47 @@ function config_sync_changes(array $config_changes, StorageInterface $source_sto
 }
 
 /**
+ * Validates a set of configuration changes during import.
+ *
+ * This hook allows modules to validate a set of configuration changes during
+ * import before we make any changes. Modules that wish to participate in this
+ * should implement hook_config_import_validate().
+ *
+ * To stop an import from happening, hook_config_import_validate()
+ * implementations should throw a ConfigImportInvalidChangeExecption and set
+ * a meaningful message.
+ *
+ * @param array $config_changes
+ *   An array of changes to be written.
+ * @param Drupal\Core\Config\StorageInterface $source_storage
+ *   The storage to synchronize configuration from.
+ * @param Drupal\Core\Config\StorageInterface $target_storage
+ *   The storage to synchronize configuration to.
+ */
+function config_import_validate_changes(array $config_changes, StorageInterface $source_storage, StorageInterface $target_storage) {
+  $changes_by_module = array();
+  foreach (array('delete', 'create', 'change') as $op) {
+    foreach ($config_changes[$op] as $key => $name) {
+      $module = strtok($name, '.');
+      if (empty($changes_by_module[$module])) {
+        $changes_by_module[$module] = array(
+          'delete' => array(),
+          'create' => array(),
+          'change' => array(),
+        );
+      }
+      $changes_by_module[$module][$op][] = $name;
+    }
+  }
+  $hook = 'config_import_validate';
+  foreach ($changes_by_module as $module => $changes) {
+    if (module_exists($module) && module_hook($module, $hook)) {
+      module_invoke($module, $hook, $changes, $source_storage, $target_storage);
+    }
+  }
+}
+
+/**
  * Imports configuration into the active configuration.
  *
  * @return bool|null
@@ -211,6 +252,15 @@ function config_import() {
     return;
   }
 
+  // Let modules validate changes before we make any changes.
+  try {
+    config_import_validate_changes($config_changes, $source_storage, $target_storage);
+  }
+  catch (ConfigException $e) {
+    watchdog_exception('config_import', $e);
+    return FALSE;
+  }
+
   if (!lock()->acquire(CONFIG_IMPORT_LOCK)) {
     // Another request is synchronizing configuration.
     // Return a negative result for UI purposes. We do not differentiate between
diff --git a/core/lib/Drupal/Core/Config/ConfigImportInvalidChangeException.php b/core/lib/Drupal/Core/Config/ConfigImportInvalidChangeException.php
new file mode 100644
index 0000000..72fbec2
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/ConfigImportInvalidChangeException.php
@@ -0,0 +1,16 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\Config\ConfigImportInvalidChangeException.
+ */
+
+namespace Drupal\Core\Config;
+
+use RuntimeException;
+
+/**
+ * An exception thrown when a set of configuration changes are invalid.
+ */
+class ConfigImportInvalidChangeException extends ConfigException {}
+
diff --git a/core/modules/config/config.api.php b/core/modules/config/config.api.php
index d845667..5f3e2de 100644
--- a/core/modules/config/config.api.php
+++ b/core/modules/config/config.api.php
@@ -13,6 +13,17 @@
  */
 
 /**
+ * Validate a set of configuration changes before import.
+ *
+ * @param array $changes
+ *   The set of changes returned from config_sync_get_changes().
+ *
+ * @throws Drupal\Core\Config\ConfigImportInvalidChangeException
+ */
+function hook_config_import_validate($changes) {
+}
+
+/**
  * Create configuration upon synchronizing configuration changes.
  *
  * This callback is invoked when configuration is synchronized between storages
diff --git a/core/modules/system/system.module b/core/modules/system/system.module
index 6dd33b1..746fa28 100644
--- a/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -6,6 +6,8 @@
  */
 
 use Drupal\Core\Utility\ModuleInfo;
+use Drupal\Core\Config\ConfigImportInvalidChangeException;
+use Drupal\Core\Config\FileStorage;
 use Drupal\Core\TypedData\Primitive;
 
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -1056,6 +1058,20 @@ function system_menu() {
 }
 
 /**
+ * Implement hook_config_import_validate().
+ */
+function system_config_import_validate($changes, $source_storage, $target_storage) {
+  // Don't allow any base config files to be deleted by an import.
+  $config_dir = drupal_get_path('module', 'system') . '/config';
+  $system_default_storage = new FileStorage($config_dir);
+  foreach ($system_default_storage->listAll() as $system_default_config_name) {
+    if (in_array($system_default_config_name, $changes['delete'])) {
+      throw new ConfigImportInvalidChangeException("Deleting default system config is invalid: '$name'.");
+    }
+  }
+}
+
+/**
  * Theme callback for the default batch page.
  */
 function _system_batch_theme() {
diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index aa5d085..1ed210e 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -1,6 +1,7 @@
 <?php
 
 use Drupal\Core\Database\Query\SelectInterface;
+use Drupal\Core\Config\ConfigImportInvalidChangeException;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\file\Plugin\Core\Entity\File;
 use Drupal\Core\Template\Attribute;
@@ -1252,6 +1253,15 @@ function user_menu() {
 }
 
 /**
+ * Implement hook_config_import_validate().
+ */
+function user_config_import_validate($changes, $source_storage, $target_storage) {
+  if (in_array('user.flood', $changes['delete'])) {
+    throw new ConfigImportInvalidChangeException("Deleting user flood stops you from being able to log in.");
+  }
+}
+
+/**
  * Implements hook_menu_site_status_alter().
  */
 function user_menu_site_status_alter(&$menu_site_status, $path) {
diff --git a/core/modules/views/views.module b/core/modules/views/views.module
index 22b5ca8..a7c2b57 100644
--- a/core/modules/views/views.module
+++ b/core/modules/views/views.module
@@ -9,6 +9,7 @@
  * incoming page and block requests.
  */
 
+use Drupal\Core\Config\ConfigImportInvalidChangeException;
 use Drupal\Core\Database\Query\AlterableInterface;
 use Drupal\views\ViewExecutable;
 use Drupal\Component\Plugin\Exception\PluginException;
@@ -479,6 +480,35 @@ function views_menu_alter(&$callbacks) {
 }
 
 /**
+ * Implement hook_config_import_validate().
+ */
+function views_config_import_validate($changes, $source_storage, $target_storage) {
+  $views = array();
+  $display_manager = drupal_container()->get('plugin.manager.views.display');
+  $display_definitions = $display_manager->getDefinitions();
+
+  foreach (array_merge($changes['create'], $changes['change']) as $name) {
+    if (strpos($name, 'views.view') === 0) {
+      $views[] = $name;
+    }
+  }
+  foreach ($views as $name) {
+    $view = entity_create('view', $source_storage->read());
+    if (!$view->id()) {
+      throw new ConfigImportInvalidChangeException('View has no id.');
+    }
+    if (!$displays = $view->get('display')) {
+      throw new ConfigImportInvalidChangeException('View has no displays.');
+    }
+    foreach ($displays as $display) {
+      if (!isset($display_definitions[$display['display_plugin']]) || !is_object($display_manager->createInstance($display['display_plugin']))) {
+        throw new ConfigImportInvalidChangeException('View display plugin cannot be found.');
+      }
+    }
+  }
+}
+
+/**
  * Helper function for menu loading. This will automatically be
  * called in order to 'load' a views argument; primarily it
  * will be used to perform validation.