diff --git a/lib/ext/Syncroton/Server.php b/lib/ext/Syncroton/Server.php
--- a/lib/ext/Syncroton/Server.php
+++ b/lib/ext/Syncroton/Server.php
@@ -52,7 +52,10 @@
         $this->_request = $request instanceof Zend_Controller_Request_Http ? $request : new Zend_Controller_Request_Http();
         $this->_body    = $body !== null ? $body : fopen('php://input', 'r');
 
-        $this->_deviceBackend = Syncroton_Registry::getDeviceBackend();
+        // Not available on unauthenticated OPTIONS request
+        if (!empty($this->_userId)) {
+            $this->_deviceBackend = Syncroton_Registry::getDeviceBackend();
+        }
 
     }
 
@@ -62,6 +65,13 @@
             $this->_logger->debug(__METHOD__ . '::' . __LINE__ . ' REQUEST METHOD: ' . $this->_request->getMethod());
         }
 
+        if ($this->_request->getMethod() != "OPTIONS" && empty($this->_userId)) {
+            $this->_logger->warn(__METHOD__ . '::' . __LINE__ . ' Not authenticated');
+            header('WWW-Authenticate: Basic realm="ActiveSync for Kolab"');
+            header('HTTP/1.1 401 Unauthorized');
+            exit;
+        }
+
         switch($this->_request->getMethod()) {
             case 'OPTIONS':
                 $this->_handleOptions();
diff --git a/lib/kolab_sync.php b/lib/kolab_sync.php
--- a/lib/kolab_sync.php
+++ b/lib/kolab_sync.php
@@ -135,12 +135,6 @@
             $userid = $this->authenticate($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW']);
         }
 
-        if (empty($userid)) {
-            header('WWW-Authenticate: Basic realm="' . $this->app_name . '"');
-            header('HTTP/1.1 401 Unauthorized');
-            exit;
-        }
-
         $this->plugins->exec_hook('ready', ['task' => 'syncroton']);
 
         // Set log directory per-user (again, in case the username changed above)
@@ -153,12 +147,15 @@
         Syncroton_Registry::set(Syncroton_Registry::LOGGERBACKEND, $this->logger);
         Syncroton_Registry::set(Syncroton_Registry::DATABASE, $this->get_dbh());
         Syncroton_Registry::set(Syncroton_Registry::TRANSACTIONMANAGER, kolab_sync_transaction_manager::getInstance());
-        Syncroton_Registry::set(Syncroton_Registry::DEVICEBACKEND, new kolab_sync_backend_device());
-        Syncroton_Registry::set(Syncroton_Registry::FOLDERBACKEND, new kolab_sync_backend_folder());
-        Syncroton_Registry::set(Syncroton_Registry::SYNCSTATEBACKEND, new kolab_sync_backend_state());
-        Syncroton_Registry::set(Syncroton_Registry::CONTENTSTATEBACKEND, new kolab_sync_backend_content());
-        Syncroton_Registry::set(Syncroton_Registry::POLICYBACKEND, new kolab_sync_backend_policy());
-        Syncroton_Registry::set(Syncroton_Registry::SLEEP_CALLBACK, [$this, 'sleep']);
+        // The unauthenticated OPTIONS request doesn't require these backends and we can't instantiate them without credentials for the underlying storage backend
+        if (!empty($userid)) {
+            Syncroton_Registry::set(Syncroton_Registry::DEVICEBACKEND, new kolab_sync_backend_device());
+            Syncroton_Registry::set(Syncroton_Registry::FOLDERBACKEND, new kolab_sync_backend_folder());
+            Syncroton_Registry::set(Syncroton_Registry::SYNCSTATEBACKEND, new kolab_sync_backend_state());
+            Syncroton_Registry::set(Syncroton_Registry::CONTENTSTATEBACKEND, new kolab_sync_backend_content());
+            Syncroton_Registry::set(Syncroton_Registry::POLICYBACKEND, new kolab_sync_backend_policy());
+            Syncroton_Registry::set(Syncroton_Registry::SLEEP_CALLBACK, [$this, 'sleep']);
+        }
 
         Syncroton_Registry::setContactsDataClass('kolab_sync_data_contacts');
         Syncroton_Registry::setCalendarDataClass('kolab_sync_data_calendar');
diff --git a/tests/Sync/OptionsTest.php b/tests/Sync/OptionsTest.php
--- a/tests/Sync/OptionsTest.php
+++ b/tests/Sync/OptionsTest.php
@@ -7,7 +7,7 @@
      */
     public function testOptions()
     {
-        $response = self::$client->request('OPTIONS', '');
+        $response = self::$client->request('OPTIONS', '', ['auth' => null]);
         $this->assertEquals(200, $response->getStatusCode());
         $this->assertStringContainsString('14', $response->getHeader('MS-Server-ActiveSync')[0]);
         $this->assertStringContainsString('14.1', $response->getHeader('MS-ASProtocolVersions')[0]);