diff --git includes/bootstrap.inc includes/bootstrap.inc
index ef2f4d1..480454a 100644
--- includes/bootstrap.inc
+++ includes/bootstrap.inc
@@ -19,7 +19,7 @@ define('DRUPAL_CORE_COMPATIBILITY', '7.x');
 /**
  * Minimum supported version of PHP.
  */
-define('DRUPAL_MINIMUM_PHP',    '5.2.0');
+define('DRUPAL_MINIMUM_PHP',    '5.2.1');
 
 /**
  * Minimum recommended value of PHP memory_limit.
diff --git includes/file.inc includes/file.inc
index 676d274..5ce4628 100644
--- includes/file.inc
+++ includes/file.inc
@@ -385,7 +385,9 @@ function file_prepare_directory(&$directory, $options = FILE_MODIFY_PERMISSIONS)
  */
 function file_ensure_htaccess() {
   file_create_htaccess('public://', FALSE);
-  file_create_htaccess('private://', TRUE);
+  if (variable_get('file_private_path', FALSE)) {
+    file_create_htaccess('private://', TRUE);
+  }
   file_create_htaccess('temporary://', TRUE);
 }
 
diff --git includes/stream_wrappers.inc includes/stream_wrappers.inc
index 183af42..97ab755 100644
--- includes/stream_wrappers.inc
+++ includes/stream_wrappers.inc
@@ -598,7 +598,7 @@ class DrupalPrivateStreamWrapper extends DrupalLocalStreamWrapper {
    * Implements abstract public function getDirectoryPath()
    */
   public function getDirectoryPath() {
-    return variable_get('file_private_path', conf_path() . '/private/files');
+    return variable_get('file_private_path', '');
   }
 
   /**
@@ -625,7 +625,7 @@ class DrupalTemporaryStreamWrapper extends DrupalLocalStreamWrapper {
    * Implements abstract public function getDirectoryPath()
    */
   public function getDirectoryPath() {
-    return variable_get('file_temporary_path', conf_path() . '/private/temp');
+    return variable_get('file_temporary_path', sys_get_temp_dir());
   }
 
   /**
diff --git index.php index.php
index c7d323b..a2210b0 100644
--- index.php
+++ index.php
@@ -18,5 +18,5 @@
 define('DRUPAL_ROOT', getcwd());
 
 require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
-drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
+drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);is_dir('private://');
 menu_execute_active_handler();
diff --git modules/system/system.admin.inc modules/system/system.admin.inc
index f11dbbb..1c2b970 100644
--- modules/system/system.admin.inc
+++ modules/system/system.admin.inc
@@ -1738,11 +1738,10 @@ function system_file_system_settings() {
     '#description' => t('A local file system path where temporary files will be stored. This directory should not be accessible over the web.'),
     '#after_build' => array('system_check_directory'),
   );
-  $wrappers = file_get_stream_wrappers();
-  $options = array(
-    'public' => $wrappers['public']['description'],
-    'private' => $wrappers['private']['description']
-  );
+  $wrappers = array_intersect_key(file_get_stream_wrappers(), array('public' => 1, 'private' => 1));
+  foreach ($wrappers as $key => $info) {
+    $options[$key] = $info['description'];
+  }
   $form['file_default_scheme'] = array(
     '#type' => 'radios',
     '#title' => t('Default download method'),
diff --git modules/system/system.install modules/system/system.install
index a14627a..e13b0ae 100644
--- modules/system/system.install
+++ modules/system/system.install
@@ -210,8 +210,9 @@ function system_requirements($phase) {
   // Test files directories.
   $directories = array(
     variable_get('file_public_path', conf_path() . '/files'),
-    variable_get('file_private_path', conf_path() . '/private/files'),
-    variable_get('file_temporary_path', conf_path() . '/private/temp'),
+    // By default no private files directory is configured.
+    variable_get('file_private_path', FALSE),
+    variable_get('file_temporary_path', sys_get_temp_dir()),
   );
   $requirements['file system'] = array(
     'title' => $t('File system'),
@@ -220,6 +221,9 @@ function system_requirements($phase) {
   $error = '';
   // For installer, create the directories if possible.
   foreach ($directories as $directory) {
+    if (!$directory) {
+      continue;
+    }
     if ($phase == 'install') {
       file_prepare_directory($directory, FILE_CREATE_DIRECTORY);
     }
diff --git modules/system/system.module modules/system/system.module
index 1f7d348..2b175bd 100644
--- modules/system/system.module
+++ modules/system/system.module
@@ -501,7 +501,8 @@ function system_menu() {
     'title' => 'File download',
     'page callback' => 'file_download',
     'page arguments' => array('private'),
-    'access callback' => TRUE,
+    'access callback' => 'variable_get',
+    'access arguments' => array('file_private_path', FALSE),
     'type' => MENU_CALLBACK,
   );
   $items['system/temporary'] = array(
@@ -1451,23 +1452,28 @@ function system_library() {
  * Implements hook_stream_wrappers().
  */
 function system_stream_wrappers() {
-  return array(
+  $wrappers = array(
     'public' => array(
       'name' => t('Public files'),
       'class' => 'DrupalPublicStreamWrapper',
       'description' => t('Public local files served by the webserver.'),
     ),
-    'private' => array(
-      'name' => t('Private files'),
-      'class' => 'DrupalPrivateStreamWrapper',
-      'description' => t('Private local files served by Drupal.'),
-    ),
     'temporary' => array(
       'name' => t('Temporary files'),
       'class' => 'DrupalTemporaryStreamWrapper',
       'description' => t('Temporary local files for upload and previews.'),
     )
   );
+  // Only register the private file stream wrapper if
+  // a file path has been set.
+  if (variable_get('file_private_path', FALSE)) {
+    $wrappers['private'] = array(
+      'name' => t('Private files'),
+      'class' => 'DrupalPrivateStreamWrapper',
+      'description' => t('Private local files served by Drupal.'),
+    );
+  }
+  return $wrappers;
 }
 
 /**
@@ -1978,6 +1984,9 @@ function system_admin_menu_block($item) {
  */
 function system_check_directory($form_element) {
   $directory = $form_element['#value'];
+  if (strlen($directory) == 0) {
+    return $form_element;
+  }
 
   if (!is_dir($directory) && !drupal_mkdir($directory, NULL, TRUE)) {
     // If the directory does not exists and cannot be created.
@@ -1990,7 +1999,7 @@ function system_check_directory($form_element) {
     form_set_error($form_element['#parents'][0], t('The directory %directory exists but is not writable and could not be made writable.', array('%directory' => $directory)));
     watchdog('file system', 'The directory %directory exists but is not writable and could not be made writable.', array('%directory' => $directory), WATCHDOG_ERROR);
   }
-  else {
+  elseif(is_dir($directory)) {
     if ($form_element['#name'] == 'file_public_path') {
       // Create public .htaccess file.
       file_create_htaccess($directory, FALSE);