diff --git a/src/Composer/Autoload/AutoloadGenerator.php b/src/Composer/Autoload/AutoloadGenerator.php
index 0691434c3..5991083f7 100644
--- a/src/Composer/Autoload/AutoloadGenerator.php
+++ b/src/Composer/Autoload/AutoloadGenerator.php
@@ -405,7 +405,7 @@ CLASSMAP;
 
         if ($targetDirLoader) {
             $file .= <<<REGISTER_AUTOLOAD
-        spl_autoload_register(array('ComposerAutoloaderInit$suffix', 'autoload'));
+        spl_autoload_register(array('ComposerAutoloaderInit$suffix', 'autoload'), true, true);
 
 
 REGISTER_AUTOLOAD;
@@ -413,7 +413,7 @@ REGISTER_AUTOLOAD;
         }
 
         $file .= <<<METHOD_FOOTER
-        \$loader->register();{$filesCode}
+        \$loader->register(true);{$filesCode}
 
         return \$loader;
     }
diff --git a/tests/Composer/Test/Autoload/Fixtures/autoload_real_files_by_dependency.php b/tests/Composer/Test/Autoload/Fixtures/autoload_real_files_by_dependency.php
index 6434b76dd..3b58316c6 100644
--- a/tests/Composer/Test/Autoload/Fixtures/autoload_real_files_by_dependency.php
+++ b/tests/Composer/Test/Autoload/Fixtures/autoload_real_files_by_dependency.php
@@ -36,7 +36,7 @@ class ComposerAutoloaderInitFilesAutoloadOrder
             $loader->addClassMap($classMap);
         }
 
-        $loader->register();
+        $loader->register(true);
 
         require $vendorDir . '/c/lorem/testC.php';
         require $vendorDir . '/z/foo/testA.php';
diff --git a/tests/Composer/Test/Autoload/Fixtures/autoload_real_functions.php b/tests/Composer/Test/Autoload/Fixtures/autoload_real_functions.php
index a25e920db..2c75be906 100644
--- a/tests/Composer/Test/Autoload/Fixtures/autoload_real_functions.php
+++ b/tests/Composer/Test/Autoload/Fixtures/autoload_real_functions.php
@@ -36,7 +36,7 @@ class ComposerAutoloaderInitFilesAutoload
             $loader->addClassMap($classMap);
         }
 
-        $loader->register();
+        $loader->register(true);
 
         require $vendorDir . '/a/a/test.php';
         require $vendorDir . '/b/b/test2.php';
diff --git a/tests/Composer/Test/Autoload/Fixtures/autoload_real_target_dir.php b/tests/Composer/Test/Autoload/Fixtures/autoload_real_target_dir.php
index ec8e392be..c9b6df98f 100644
--- a/tests/Composer/Test/Autoload/Fixtures/autoload_real_target_dir.php
+++ b/tests/Composer/Test/Autoload/Fixtures/autoload_real_target_dir.php
@@ -36,9 +36,9 @@ class ComposerAutoloaderInitTargetDir
             $loader->addClassMap($classMap);
         }
 
-        spl_autoload_register(array('ComposerAutoloaderInitTargetDir', 'autoload'));
+        spl_autoload_register(array('ComposerAutoloaderInitTargetDir', 'autoload'), true, true);
 
-        $loader->register();
+        $loader->register(true);
 
         return $loader;
     }