diff --git a/core/modules/block/block.install b/core/modules/block/block.install
index de652be..c0971c3 100644
--- a/core/modules/block/block.install
+++ b/core/modules/block/block.install
@@ -21,20 +21,27 @@ function block_update_8001() {
     'user' => 'user.current_user_context',
   ];
 
+  // Provides a hardcoded list of UI labels for each condition plugins. Sadly
+  // they are not machine accessible, see
+  // \Drupal\node\Plugin\Condition\NodeType::buildConfigurationForm.
   $condition_plugin_id_ui_label_map = [
     'node_type' => \Drupal::translation()->translate('Content types'),
     'request_path' => \Drupal::translation()->translate('Pages'),
     'user_role' => \Drupal::translation()->translate('Roles'),
   ];
 
-  $config_factory = \Drupal::configFactory();
-  $message = NULL;
-  $disabled_blocks = $problematic_visibility_plugins = $backup_values = [];
+  $condition_plugin_id_label_map = array_map(function($definition) {
+    return $definition['label'];
+  }, \Drupal::service('plugin.manager.condition')->getDefinitions());
+
   // We deal with config objects directly in order to avoid invoking Entity API
   // hooks. They can be problematic when two modules implement a specific hook,
   // their code is updated at the same time, yet the update functions run
   // sequentially so the second hook implementation can not rely on the data not
   // being altered by the first hook.
+  $config_factory = \Drupal::configFactory();
+  $message = NULL;
+  $disabled_blocks = $problematic_visibility_plugins = $backup_values = [];
 
   $update_backup = [];
   foreach ($config_factory->listAll('block.block.') as $block_config_name) {
@@ -49,7 +56,7 @@ function block_update_8001() {
             // modules can run their own update functions to update mappings
             // that they provide.
             $disabled_blocks[$block->get('id')] = $block->get('settings.label');
-            $problematic_visibility_plugins[$block->get('id')][] = $condition_plugin_id_ui_label_map[$condition_plugin_id];
+            $problematic_visibility_plugins[$block->get('id')][] = isset($condition_plugin_id_ui_label_map[$condition_plugin_id]) ? $condition_plugin_id_ui_label_map[$condition_plugin_id] : $condition_plugin_id_label_map[$condition_plugin_id];
 
             $backup_values[] = $context;
             unset($visibility[$condition_plugin_id]);
@@ -61,8 +68,7 @@ function block_update_8001() {
       }
       if (isset($disabled_blocks[$block->get('id')])) {
         // This block will have an invalid context mapping service and must be
-        // disabled to avoid the 'You must provide the context IDs in the
-        // @{service_id}:{unqualified_context_id} format' exception.
+        // disabled in order to prevent information disclosure.
         $block->set('status', FALSE);
       }
       $block->set('visibility', $visibility);
@@ -80,10 +86,10 @@ function block_update_8001() {
   }
 
   if ($disabled_blocks) {
-    $message = \Drupal::translation()->translate('Encountered an unexpected context mapping key, one or more mappings could not be updated. Please manually review your visibility settings for the following blocks, which are disabled now:');
+    $message = \Drupal::translation()->translate('Encountered a context mapping key coming probably from a contrib module: One or more mappings could not be updated. Please manually review your visibility settings for the following blocks, which are disabled now:');
     $message .= '<ul>';
     foreach ($disabled_blocks as $disabled_block_id => $disabled_block_label) {
-      $message .= '<li>' . $disabled_block_label . ' (' . \Drupal::translation()->translate('Visibility') . ': ' . implode(', ', $problematic_visibility_plugins[$disabled_block_id]) . ')</li>';
+      $message .= '<li>' . Drupal::translation()->translate('@label (Visibility: @plugin_ids)', ['@label' => $disabled_block_label, '@plugin_ids' => implode(', ', $problematic_visibility_plugins[$disabled_block_id])]) . '</li>';
     }
     $message .= '</ul>';
   }
diff --git a/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php b/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
index e05efb7..5a10a69 100644
--- a/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
+++ b/core/modules/block/src/Tests/Update/BlockContextMappingUpdateTest.php
@@ -32,11 +32,11 @@ protected function setUp() {
   }
 
   /**
-   * Tests that block context mapping are updated properly.
+   * Tests that block context mapping is updated properly.
    */
   public function testUpdateHookN() {
     $this->runUpdates();
-    $this->assertRaw('Encountered an unexpected context mapping key, one or more mappings could not be updated. Please manually review your visibility settings for the following blocks, which are disabled now:<ul><li>User login (Visibility: Content types)</li></ul>');
+    $this->assertRaw('Encountered a context mapping key coming probably from a contrib module: One or more mappings could not be updated. Please manually review your visibility settings for the following blocks, which are disabled now:<ul><li>User login (Visibility: Content types)</li></ul>');
 
     // Disable maintenance mode.
     \Drupal::state()->set('system.maintenance_mode', FALSE);