diff -u b/includes/bootstrap.inc b/includes/bootstrap.inc
--- b/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -837,14 +837,6 @@
   // drupal_static().
   static $files = array(), $dirs = array();
 
-  // We use drupal_static() for the missing records so we can test it.
-  // drupal_static_fast() is used as this function may be called often.
-  static $drupal_static_fast;
-  if (!isset($drupal_static_fast)) {
-    $drupal_static_fast['missing'] = &drupal_static('drupal_get_filename:missing');
-  }
-  $missing = &$drupal_static_fast['missing'];
-
   // Profiles are a special case: they have a fixed location and naming.
   if ($type == 'profile') {
     $profile_filename = "profiles/$name/$name.profile";
@@ -881,6 +873,9 @@
     // Fallback to searching the filesystem if the database could not find the
     // file or the file returned by the database is not found.
     if (!isset($files[$type][$name])) {
+      // We use drupal_static() for the missing records so we can test it.
+      $missing = &drupal_static('drupal_get_filename:missing');
+
       // We have a consistent directory naming: modules, themes...
       $dir = $type . 's';
       if ($type == 'theme_engine') {
@@ -897,9 +892,16 @@
       // See if we have a cached list of files missing from the file system.
       if (!isset($missing)) {
         $missing = array();
-        $cache = cache_get('drupal_get_filename:missing');
-        if (!empty($cache->data)) {
-          $missing = $cache->data;
+        try {
+          if (function_exists('cache_get')) {
+            $cache = cache_get('drupal_get_filename:missing');
+            if (!empty($cache->data)) {
+              $missing = $cache->data;
+            }
+          }
+        }
+        catch (Exception $e) {
+          // Hide the error.
         }
       }
 
@@ -929,9 +931,16 @@
       // This cache will be cleared on cron runs as well as when visiting the
       // module and theme list pages.
       $missing[$type][$name] = TRUE;
-      cache_set('drupal_get_filename:missing', $missing, 'cache', REQUEST_TIME + 24 * 60 * 60);
+      try {
+        if (function_exists('cache_set')) {
+          cache_set('drupal_get_filename:missing', $missing, 'cache');
+        }
+      }
+      catch (Exception $e) {
+        // Hide the error.
+      }
     }
-    trigger_error(t('The following @type is missing from the file system: @name. For more information, see <a href="@documentation">the documentation page</a>.', array('@type' => $type, '@name' => $name, '@documentation' => 'https://www.drupal.org/node/2487215')), E_USER_WARNING);
+    trigger_error(format_string('The following @type is missing from the file system: @name. For more information, see <a href="@documentation">the documentation page</a>.', array('@type' => $type, '@name' => $name, '@documentation' => 'https://www.drupal.org/node/2487215')), E_USER_WARNING);
   }
 }
 
diff -u b/modules/simpletest/tests/bootstrap.test b/modules/simpletest/tests/bootstrap.test
--- b/modules/simpletest/tests/bootstrap.test
+++ b/modules/simpletest/tests/bootstrap.test
@@ -382,6 +382,11 @@
   }
 
   /**
+   * @var bool
+   */
+  protected $getFilenameTestTriggeredError = FALSE;
+
+  /**
    * Test that drupal_get_filename() works correctly when the file is not found in the database.
    */
   function testDrupalGetFilename() {
@@ -412,7 +417,7 @@
     $this->assertIdentical(drupal_get_filename('script', 'test'), 'scripts/test.script', t('Retrieve test script location.'));
 
     // Generate a non-existing module name.
-    $non_existing_module = uniqid("", TRUE);
+    $non_existing_module = $this->randomName();
 
     // We save that the error handler is triggered by drupal_get_filename().
     // This variable is inherited in the error handler with 'use'.
@@ -420,17 +425,9 @@
 
     // Searching for an item that does not exist returns NULL.
     // Set a custom error handler so we can ignore the file not found error.
-    set_error_handler(function($error_level, $message, $filename, $line, $context) use (&$get_filename_test_triggered_error) {
-      // Skip error handling if this is a "file not found" error.
-      if (strstr($message, 'is missing from the file system:')) {
-        $get_filename_test_triggered_error = TRUE;
-        return;
-      }
-      _drupal_error_handler($error_level, $message, $filename, $line, $context);
-    });
-
+    set_error_handler(array($this, 'fileNotFoundErrorHandler'));
     $this->assertNull(drupal_get_filename('module', $non_existing_module), 'Searching for an item that does not exist returns NULL.');
-    $this->assertTrue($get_filename_test_triggered_error, 'Searching for an item that does not exist triggers an error.');
+    $this->assertTrue($this->getFilenameTestTriggeredError, 'Searching for an item that does not exist triggers an error.');
     // Restore the original error handler.
     restore_error_handler();
 
@@ -442,4 +439,13 @@
     $this->assertTrue($missing['module'][$non_existing_module], 'Searching for an item that does not exist creates a static record in drupal_get_filename().');
   }
+
+  public function fileNotFoundErrorHandler($error_level, $message, $filename, $line, $context) {
+    // Skip error handling if this is a "file not found" error.
+    if (strstr($message, 'is missing from the file system:')) {
+      $this->getFilenameTestTriggeredError = TRUE;
+      return;
+    }
+    _drupal_error_handler($error_level, $message, $filename, $line, $context);
+  }
 }
 
reverted:
--- b/modules/system/system.admin.inc
+++ a/modules/system/system.admin.inc
@@ -134,10 +134,6 @@
  * Menu callback; displays a listing of all themes.
  */
 function system_themes_page() {
-  // Clean up the bootstrap "missing files" cache when listing themes.
-  drupal_static_reset('drupal_get_filename:missing');
-  cache_clear_all('drupal_get_filename:missing', 'cache');
-
   // Get current list of themes.
   $themes = system_rebuild_theme_data();
   uasort($themes, 'system_sort_modules_by_info_name');
@@ -792,10 +788,6 @@
  * @see system_modules_submit()
  */
 function system_modules($form, $form_state = array()) {
-  // Clean up the bootstrap "missing modules" cache when listing modules.
-  drupal_static_reset('drupal_get_filename:missing');
-  cache_clear_all('drupal_get_filename:missing', 'cache');
-
   // Get current list of modules.
   $files = system_rebuild_module_data();
 
only in patch2:
unchanged:
--- a/modules/system/system.module
+++ b/modules/system/system.module
@@ -2365,6 +2365,10 @@ function system_get_info($type, $name = NULL) {
  *   An associative array of module information.
  */
 function _system_rebuild_module_data() {
+  // Clean up the bootstrap "missing files" cache when rebuilding theme data.
+  drupal_static_reset('drupal_get_filename:missing');
+  cache_clear_all('drupal_get_filename:missing', 'cache');
+
   // Find modules
   $modules = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.module$/', 'modules', 'name', 0);
 
@@ -2501,6 +2505,10 @@ function _system_update_bootstrap_status() {
  *   An associative array of themes information.
  */
 function _system_rebuild_theme_data() {
+  // Clean up the bootstrap "missing files" cache when rebuilding theme data.
+  drupal_static_reset('drupal_get_filename:missing');
+  cache_clear_all('drupal_get_filename:missing', 'cache');
+
   // Find themes
   $themes = drupal_system_listing('/^' . DRUPAL_PHP_FUNCTION_PATTERN . '\.info$/', 'themes');
   // Allow modules to add further themes.