diff -u b/includes/bootstrap.inc b/includes/bootstrap.inc
--- b/includes/bootstrap.inc
+++ b/includes/bootstrap.inc
@@ -828,15 +828,15 @@
  * @param $filename
  *   The filename of the item if it is to be set explicitly rather
  *   than by consulting the database.
- * @param boolean $create_errors
- *   Whether to create an error when a file is missing / moved. Defaults to
+ * @param bool $trigger_error
+ *   Whether to trigger an error when a file is missing / moved. Defaults to
  *   TRUE, but we may want to set this to FALSE if we merely want to check
  *   whether an item is installed.
  *
  * @return
  *   The filename of the requested item or NULL if the item is not found.
  */
-function drupal_get_filename($type, $name, $filename = NULL, $create_errors = TRUE) {
+function drupal_get_filename($type, $name, $filename = NULL, $trigger_error = TRUE) {
   // The location of files will not change during the request, so do not use
   // drupal_static().
   // The $files static variable will hold the locations of all requested files.
@@ -896,16 +896,16 @@
     // Fall back to searching the filesystem if the database could not find the
     // file or the file does not exist at the path returned by the database.
     if (!isset($files[$type][$name])) {
-      $files[$type][$name] = _drupal_get_filename_fallback($type, $name, $create_errors);
+      $files[$type][$name] = _drupal_get_filename_fallback($type, $name, $trigger_error);
     }
   }
 
   if (isset($files[$type][$name])) {
     // We found a file.
     $file_scans = &drupal_static('_drupal_get_filename_fallback');
-    // If this file had previously been marked as missing or moved, clean up
-    // the entry from the file scan cache.
-    if (isset($file_scans[$type][$name])) {
+    // If this file had previously been marked as missing, clean up the entry
+    // from the file scan cache.
+    if (isset($file_scans[$type][$name]) && $file_scans[$type][$name] === FALSE) {
       $file_scans[$type][$name] = NULL;
       $file_scans['#write_cache'] = TRUE;
     }
@@ -925,13 +925,13 @@
  *   The type of the item (theme, theme_engine, module, profile).
  * @param string $name
  *   The name of the item for which the filename is requested.
- * @param boolean $create_errors
+ * @param bool $trigger_error
  *   Whether to create an error when a file is missing or moved.
  *
  * @return string
  *   The filename of the requested item or NULL if the item is not found.
  */
-function _drupal_get_filename_fallback($type, $name, $create_errors) {
+function _drupal_get_filename_fallback($type, $name, $trigger_error) {
   // This static variable will hold all missing and moved files, in order
   // to prevent unnecessary file scans. It is an associative array with as
   // keys the type and name of the item, and as value:
@@ -982,14 +982,14 @@
     if (isset($system_filepaths[$type][$name]) && $system_filepaths[$type][$name] != $filename_from_file_scan) {
       // Make sure our change to the file scan cache will be written to
       // the persistent cache.
-      if ($file_scans[$type][$name] != $filename_from_file_scan) {
+      if (!isset($file_scans[$type][$name]) || isset($file_scans[$type][$name]) && $file_scans[$type][$name] != $filename_from_file_scan) {
         $file_scans['#write_cache'] = TRUE;
       }
       // This file has moved. Store its new location in the file scan cache.
       $file_scans[$type][$name] = $filename_from_file_scan;
       // Create a user-level warning about the moved file.
-      if ($create_errors) {
-        _drupal_get_filename_fallback_create_error($type, $name, 'moved');
+      if ($trigger_error) {
+        _drupal_get_filename_fallback_trigger_error($type, $name, 'moved');
       }
     }
     return $filename_from_file_scan;
@@ -1003,8 +1003,8 @@
     // Mark the file as missing.
     $file_scans[$type][$name] = FALSE;
     // Create a user-level warning about the missing file.
-    if ($create_errors) {
-      _drupal_get_filename_fallback_create_error($type, $name, 'missing');
+    if ($trigger_error) {
+      _drupal_get_filename_fallback_trigger_error($type, $name, 'missing');
     }
   }
 }
@@ -1022,17 +1022,17 @@
  * @param $error_type
  *   The type of the error ('missing' or 'moved').
  */
-function _drupal_get_filename_fallback_create_error($type, $name, $error_type) {
+function _drupal_get_filename_fallback_trigger_error($type, $name, $error_type) {
   // Make sure we only show any missing/moved file error only once per request.
-  static $errors_created = array();
-  if (empty($errors_created[$type][$name][$error_type])) {
+  static $errors_triggered = array();
+  if (empty($errors_triggered[$type][$name][$error_type])) {
     if ($error_type == 'missing') {
       trigger_error(format_string('The following %type is missing from the file system: %name. In order to fix this, put the file back in its original location or uninstall the module. For more information, see <a href="@documentation">the documentation page</a>.', array('%type' => $type, '%name' => $name, '@documentation' => 'https://www.drupal.org/node/2487215')), E_USER_WARNING);
     }
     elseif ($error_type == 'moved') {
-      trigger_error(format_string('The following %type has moved on the file system: %name. In order to fix this, clear caches or put the file back in its original location. 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 has moved within the file system: %name. In order to fix this, clear caches or put the file back in its original location. 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);
     }
-    $errors_created[$type][$name][$error_type] = TRUE;
+    $errors_triggered[$type][$name][$error_type] = TRUE;
   }
 }