diff --git modules/update/update.manager.inc modules/update/update.manager.inc
index 4f55b1b..636aa97 100644
--- modules/update/update.manager.inc
+++ modules/update/update.manager.inc
@@ -729,25 +729,62 @@ function update_manager_install_form_submit($form, &$form_state) {
  */
 
 /**
+ * Return a short unique identifier for this Drupal installation.
+ *
+ * @return
+ *   An eight character string uniquely identifying this Drupal installation.
+ */
+function _update_manager_unique_identifier() {
+  $id = &drupal_static(__FUNCTION__, '');
+  if (empty($id)) {
+    $id = substr(hash('sha256', drupal_get_hash_salt()), 0, 8);
+  }
+  return $id;
+}
+
+/**
  * Return the directory where update archive files should be extracted.
  *
- * If the directory does not already exist, attempt to create it.
+ * @param $create
+ *   If TRUE, attempt to create the directory if it does not already exist.
  *
  * @return
  *   The full path to the temporary directory where update file archives
  *   should be extracted.
  */
-function _update_manager_extract_directory() {
+function _update_manager_extract_directory($create = TRUE) {
+  $directory = &drupal_static(__FUNCTION__, '');
+  if (empty($directory)) {
+    $directory = 'temporary://update-extraction-' . _update_manager_unique_identifier();
+    if ($create && !file_exists($directory)) {
+      mkdir($directory);
+    }
+  }
+  return $directory;
+}
+
+/**
+ * Return the directory where update archive files should be cached.
+ *
+ * @param $create
+ *   If TRUE, attempt to create the directory if it does not already exist.
+ *
+ * @return
+ *   The full path to the temporary directory where update file archives
+ *   should be cached.
+ */
+function _update_manager_cache_directory($create = TRUE) {
   $directory = &drupal_static(__FUNCTION__, '');
   if (empty($directory)) {
-    $directory = 'temporary://update-extraction';
-    if (!file_exists($directory)) {
+    $directory = 'temporary://update-cache-' . _update_manager_unique_identifier();
+    if ($create && !file_exists($directory)) {
       mkdir($directory);
     }
   }
   return $directory;
 }
 
+
 /**
  * Unpack a downloaded archive file.
  *
@@ -823,13 +860,9 @@ function update_manager_file_get($url) {
   }
 
   // Check the cache and download the file if needed.
-  $cache_directory = 'temporary://update-cache';
+  $cache_directory = _update_manager_cache_directory();
   $local = $cache_directory . '/' . basename($parsed_url['path']);
 
-  if (!file_exists($cache_directory)) {
-    mkdir($cache_directory);
-  }
-
   if (!file_exists($local) || update_delete_file_if_stale($local)) {
     return system_retrieve_file($url, $local, FALSE, FILE_EXISTS_REPLACE);
   }
diff --git modules/update/update.module modules/update/update.module
index c5551e2..ed9b646 100644
--- modules/update/update.module
+++ modules/update/update.module
@@ -861,10 +861,11 @@ function update_flush_caches() {
  * Clear the temporary files and directories based on file age from disk.
  */
 function update_clear_update_disk_cache() {
-  // List of update module cache directories.
+  // List of update module cache directories. Do not create the directories if
+  // they do not exist.
   $directories = array(
-    'temporary://update-cache',
-    'temporary://update-extraction',
+    _update_manager_cache_directory(FALSE),
+    _update_manager_extract_directory(FALSE),
   );
 
   // Search for files and directories in base folder only without recursion.