diff --git a/core/Controller/LostController.php b/core/Controller/LostController.php
index 13fb6fee5c..86f9e7478e 100644
--- a/core/Controller/LostController.php
+++ b/core/Controller/LostController.php
@@ -223,6 +223,12 @@ class LostController extends Controller {
 			return new JSONResponse($this->error($this->l10n->t('Password reset is disabled')));
 		}
 
+		\OCP\Util::emitHook(
+			'\OCA\Files_Sharing\API\Server2Server',
+			'preLoginNameUsedAsUserName',
+			['uid' => &$user]
+		);
+
 		// FIXME: use HTTP error codes
 		try {
 			$this->sendEmail($user);
diff --git a/lib/private/User/Manager.php b/lib/private/User/Manager.php
index 8f3c98d4b5..2d3ce7ebe3 100644
--- a/lib/private/User/Manager.php
+++ b/lib/private/User/Manager.php
@@ -154,16 +154,6 @@ class Manager extends PublicEmitter implements IUserManager {
 			return $this->cachedUsers[$uid];
 		}
 
-		if (method_exists($backend, 'loginName2UserName')) {
-			$loginName = $backend->loginName2UserName($uid);
-			if ($loginName !== false) {
-				$uid = $loginName;
-			}
-			if (isset($this->cachedUsers[$uid])) {
-				return $this->cachedUsers[$uid];
-			}
-		}
-
 		$user = new User($uid, $backend, $this, $this->config);
 		if ($cacheUser) {
 			$this->cachedUsers[$uid] = $user;
diff --git a/tests/lib/User/ManagerTest.php b/tests/lib/User/ManagerTest.php
index 02200b05d0..badcfb551b 100644
--- a/tests/lib/User/ManagerTest.php
+++ b/tests/lib/User/ManagerTest.php
@@ -184,9 +184,8 @@ class ManagerTest extends TestCase {
 			->method('userExists')
 			->with($this->equalTo('foo'))
 			->will($this->returnValue(true));
-		$backend->expects($this->once())
-			->method('loginName2UserName')
-			->willReturn(false);
+		$backend->expects($this->never())
+			->method('loginName2UserName');
 
 		$manager = new \OC\User\Manager($this->config);
 		$manager->registerBackend($backend);
@@ -210,6 +209,24 @@ class ManagerTest extends TestCase {
 		$this->assertEquals(null, $manager->get('foo'));
 	}
 
+	public function testGetOneBackendDoNotTranslateLoginNames() {
+		/**
+		 * @var \Test\Util\User\Dummy | \PHPUnit_Framework_MockObject_MockObject $backend
+		 */
+		$backend = $this->createMock(\Test\Util\User\Dummy::class);
+		$backend->expects($this->once())
+			->method('userExists')
+			->with($this->equalTo('bLeNdEr'))
+			->will($this->returnValue(true));
+		$backend->expects($this->never())
+			->method('loginName2UserName');
+
+		$manager = new \OC\User\Manager($this->config);
+		$manager->registerBackend($backend);
+
+		$this->assertEquals('bLeNdEr', $manager->get('bLeNdEr')->getUID());
+	}
+
 	public function testSearchOneBackend() {
 		/**
 		 * @var \Test\Util\User\Dummy | \PHPUnit_Framework_MockObject_MockObject $backend
@@ -219,6 +236,8 @@ class ManagerTest extends TestCase {
 			->method('getUsers')
 			->with($this->equalTo('fo'))
 			->will($this->returnValue(array('foo', 'afoo')));
+		$backend->expects($this->never())
+			->method('loginName2UserName');
 
 		$manager = new \OC\User\Manager($this->config);
 		$manager->registerBackend($backend);
@@ -238,9 +257,8 @@ class ManagerTest extends TestCase {
 			->method('getUsers')
 			->with($this->equalTo('fo'), $this->equalTo(3), $this->equalTo(1))
 			->will($this->returnValue(array('foo1', 'foo2')));
-		$backend1->expects($this->exactly(2))
-			->method('loginName2UserName')
-			->willReturn(false);
+		$backend1->expects($this->never())
+			->method('loginName2UserName');
 
 		/**
 		 * @var \Test\Util\User\Dummy | \PHPUnit_Framework_MockObject_MockObject $backend2
@@ -250,9 +268,8 @@ class ManagerTest extends TestCase {
 			->method('getUsers')
 			->with($this->equalTo('fo'), $this->equalTo(3), $this->equalTo(1))
 			->will($this->returnValue(array('foo3')));
-		$backend2->expects($this->once())
-			->method('loginName2UserName')
-			->willReturn(false);
+		$backend2->expects($this->never())
+			->method('loginName2UserName');
 
 		$manager = new \OC\User\Manager($this->config);
 		$manager->registerBackend($backend1);
@@ -333,9 +350,8 @@ class ManagerTest extends TestCase {
 			->method('userExists')
 			->with($this->equalTo('foo'))
 			->will($this->returnValue(false));
-		$backend->expects($this->once())
-			->method('loginName2UserName')
-			->willReturn(false);
+		$backend->expects($this->never())
+			->method('loginName2UserName');
 
 		$manager = new \OC\User\Manager($this->config);
 		$manager->registerBackend($backend);