diff --git a/apps/files/command/transferownership.php b/apps/files/command/transferownership.php
index d3994bbdf9f58..96ed8fbbb8465 100644
--- a/apps/files/command/transferownership.php
+++ b/apps/files/command/transferownership.php
@@ -28,6 +28,7 @@
 use OC\Files\View;
 use OCP\Files\FileInfo;
 use OCP\Files\Mount\IMountManager;
+use OCP\IUser;
 use OCP\IUserManager;
 use OCP\Share\IManager;
 use OCP\Share\IShare;
@@ -92,15 +93,21 @@ protected function configure() {
 	protected function execute(InputInterface $input, OutputInterface $output) {
 		$this->sourceUser = $input->getArgument('source-user');
 		$this->destinationUser = $input->getArgument('destination-user');
-		if (!$this->userManager->userExists($this->sourceUser)) {
+		$source = $this->userManager->get($this->sourceUser);
+		$destination = $this->userManager->get($this->destinationUser);
+
+		if (!$source instanceof IUser) {
 			$output->writeln("<error>Unknown source user $this->sourceUser</error>");
 			return;
 		}
-		if (!$this->userManager->userExists($this->destinationUser)) {
+		if (!$destination instanceof IUser) {
 			$output->writeln("<error>Unknown destination user $this->destinationUser</error>");
 			return;
 		}
-		
+
+		$this->sourceUser = $source->getUID();
+		$this->destinationUser = $destination->getUID();
+
 		// target user has to be ready
 		if (!\OC::$server->getEncryptionManager()->isReadyForUser($this->destinationUser)) {
 			$output->writeln("<error>The target user is not ready to accept files. The user has at least to be logged in once.</error>");
diff --git a/lib/private/user/manager.php b/lib/private/user/manager.php
index eb86873a26f2b..e638823ad297a 100644
--- a/lib/private/user/manager.php
+++ b/lib/private/user/manager.php
@@ -155,6 +155,16 @@ protected function getUserObject($uid, $backend, $cacheUser = true) {
 			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;