Index: t3lib/core_autoload.php
===================================================================
--- t3lib/core_autoload.php	(revision 9253)
+++ t3lib/core_autoload.php	(revision )
@@ -176,8 +176,5 @@
 
 $tslibClasses = require(PATH_typo3 . 'sysext/cms/ext_autoload.php');
 
-$emClasses = array();
-$emClasses = require(PATH_typo3 . 'sysext/em/ext_autoload.php');
-
-return array_merge($t3libClasses, $tslibClasses, $emClasses);
+return array_merge($t3libClasses, $tslibClasses);
 ?>
Index: t3lib/class.t3lib_autoloader.php
===================================================================
--- t3lib/class.t3lib_autoloader.php	(revision 8804)
+++ t3lib/class.t3lib_autoloader.php	(revision )
@@ -155,7 +155,11 @@
 	 */
 	static protected function attemptToLoadRegistryForGivenClassName($className) {
 		$classNameParts = explode('_', $className);
+		if ($classNameParts[0] === 'em') {
+			$extensionPrefix = 'tx_em';
+		} else {
-		$extensionPrefix = array_shift($classNameParts) . '_' . array_shift($classNameParts);
+			$extensionPrefix = array_shift($classNameParts) . '_' . array_shift($classNameParts);
+		}
 		$extensionKey = t3lib_extMgm::getExtensionKeyByPrefix($extensionPrefix);
 
 		if (!$extensionKey || array_key_exists($extensionKey, self::$extensionHasAutoloadConfiguration)) {