diff --git a/core/lib/Drupal/Core/Config/Config.php b/core/lib/Drupal/Core/Config/Config.php
index f78d4d7..c2269ae 100644
--- a/core/lib/Drupal/Core/Config/Config.php
+++ b/core/lib/Drupal/Core/Config/Config.php
@@ -582,7 +582,7 @@ protected function getSchemaWrapper() {
    * @return mixed
    *   The value cast to the type indicated in the schema.
    *
-   * @throws \Drupal\Core\Config\UnsupportedConfigDataTypeException
+   * @throws \Drupal\Core\Config\UnsupportedDataTypeConfigException
    *   Exception on unsupported/undefined data type deducted.
    */
   protected function castValue($key, $value) {
@@ -621,7 +621,7 @@ protected function castValue($key, $value) {
     else {
       // Throw exception on any non-scalar or non-array value.
       if (!is_array($value)) {
-        throw new UnsupportedConfigDataTypeException(format_string('Invalid data type for config element @name:@key', array(
+        throw new UnsupportedDataTypeConfigException(String::format('Invalid data type for config element @name:@key', array(
           '@name' => $this->getName(),
           '@key' => $key,
         )));
diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index 52644a1..6ee1238 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -7,7 +7,9 @@
 
 namespace Drupal\Core\Config;
 
+use Drupal\Component\Utility\String;
 use Symfony\Component\Yaml\Dumper;
+use Symfony\Component\Yaml\Exception\DumpException;
 use Symfony\Component\Yaml\Parser;
 
 /**
@@ -105,11 +107,17 @@ public function readMultiple(array $names) {
   /**
    * Implements Drupal\Core\Config\StorageInterface::write().
    *
-   * @throws Symfony\Component\Yaml\Exception\DumpException
+   * @throws \Drupal\Core\Config\UnsupportedDataTypeConfigException
    * @throws \Drupal\Core\Config\StorageException
    */
   public function write($name, array $data) {
-    $data = $this->encode($data);
+    try {
+      $data = $this->encode($data);
+    }
+    catch(DumpException $e) {
+      throw new UnsupportedDataTypeConfigException(String::format('Invalid data type for used in config: @name', array('@name' => $name)));
+    }
+
     $target = $this->getFilePath($name);
     $status = @file_put_contents($target, $data);
     if ($status === FALSE) {
diff --git a/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
index a46f1e5..7576163 100644
--- a/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
+++ b/core/modules/config/lib/Drupal/config/Tests/ConfigCRUDTest.php
@@ -7,10 +7,11 @@
 
 namespace Drupal\config\Tests;
 
+use Drupal\Component\Utility\String;
 use Drupal\Core\Config\ConfigNameException;
 use Drupal\simpletest\DrupalUnitTestBase;
 use Drupal\Core\Config\FileStorage;
-use Drupal\Core\Config\UnsupportedConfigDataTypeException;
+use Drupal\Core\Config\UnsupportedDataTypeConfigException;
 
 /**
  * Tests CRUD operations on configuration objects.
@@ -226,12 +227,31 @@ public function testDataTypes() {
     $this->assertIdentical($config->get(), $data);
     $this->assertIdentical($storage->read($name), $data);
 
+    // Test that setting an unsupported type for a config object with a schema
+    // fails.
     try {
       $config->set('stream', fopen(__FILE__, 'r'))->save();
       $this->fail('No Exception thrown upon saving invalid data type.');
     }
-    catch (UnsupportedConfigDataTypeException $e) {
-      $this->pass(format_string('%class thrown upon saving invalid data type.', array(
+    catch (UnsupportedDataTypeConfigException $e) {
+      $this->pass(String::format('%class thrown upon saving invalid data type.', array(
+        '%class' => get_class($e),
+      )));
+    }
+
+    // Test that setting an unsupported type for a config object with no schema
+    // also fails.
+    $typed_config_manager = $this->container->get('config.typed');
+    $config_name = 'config_test.no_schema';
+    $config = $this->container->get('config.factory')->get($config_name);
+    $this->assertFalse($typed_config_manager->hasConfigSchema($config_name));
+
+    try {
+      $config->set('stream', fopen(__FILE__, 'r'))->save();
+      $this->fail('No Exception thrown upon saving invalid data type.');
+    }
+    catch (UnsupportedDataTypeConfigException $e) {
+      $this->pass(String::format('%class thrown upon saving invalid data type.', array(
         '%class' => get_class($e),
       )));
     }