diff --git a/apps/files_sharing/lib/external/manager.php b/apps/files_sharing/lib/external/manager.php
index 968edba089..35dcabbe50 100644
--- a/apps/files_sharing/lib/external/manager.php
+++ b/apps/files_sharing/lib/external/manager.php
@@ -199,7 +199,7 @@ class Manager {
 		$data['manager'] = $this;
 		$mountPoint = '/' . $this->uid . '/files' . $data['mountpoint'];
 		$data['mountpoint'] = $mountPoint;
-		$data['certificateManager'] = \OC::$server->getCertificateManager(\OC::$server->getUserSession()->getUser());
+		$data['certificateManager'] = \OC::$server->getCertificateManager($this->uid);
 		$mount = new Mount(self::STORAGE, $mountPoint, $data, $this, $this->storageLoader);
 		$this->mountManager->addMount($mount);
 		return $mount;
diff --git a/apps/files_sharing/lib/hooks.php b/apps/files_sharing/lib/hooks.php
index 6f23c103b1..10e16be4a9 100644
--- a/apps/files_sharing/lib/hooks.php
+++ b/apps/files_sharing/lib/hooks.php
@@ -30,8 +30,8 @@ class Hooks {
 			\OC::$server->getDatabaseConnection(),
 			\OC\Files\Filesystem::getMountManager(),
 			\OC\Files\Filesystem::getLoader(),
-			\OC::$server->getUserSession(),
-			\OC::$server->getHTTPHelper());
+			\OC::$server->getHTTPHelper(),
+			$params['uid']);
 
 		$manager->removeUserShares($params['uid']);
 	}
diff --git a/apps/files_sharing/tests/server2server.php b/apps/files_sharing/tests/server2server.php
index 2d59f7be9c..6e9c0dd0dd 100644
--- a/apps/files_sharing/tests/server2server.php
+++ b/apps/files_sharing/tests/server2server.php
@@ -153,8 +153,9 @@ class Test_Files_Sharing_S2S_OCS_API extends TestCase {
 			\OC::$server->getDatabaseConnection(),
 			\OC\Files\Filesystem::getMountManager(),
 			\OC\Files\Filesystem::getLoader(),
-			\OC::$server->getUserSession(),
-			\OC::$server->getHTTPHelper());
+			\OC::$server->getHTTPHelper(),
+			$toDelete
+			);
 
 		$manager->removeUserShares($toDelete);
 
diff --git a/lib/private/security/certificatemanager.php b/lib/private/security/certificatemanager.php
index 4a8ea17073..0744546177 100644
--- a/lib/private/security/certificatemanager.php
+++ b/lib/private/security/certificatemanager.php
@@ -16,15 +16,15 @@ use OCP\ICertificateManager;
  */
 class CertificateManager implements ICertificateManager {
 	/**
-	 * @var \OCP\IUser
+	 * @var string
 	 */
-	protected $user;
+	protected $uid;
 
 	/**
-	 * @param \OCP\IUser $user
+	 * @param string $uid
 	 */
-	public function __construct($user) {
-		$this->user = $user;
+	public function __construct($uid) {
+		$this->uid = $uid;
 	}
 
 	/**
@@ -134,7 +134,7 @@ class CertificateManager implements ICertificateManager {
 	}
 
 	private function getPathToCertificates() {
-		$path = $this->user ? $this->user->getHome() . '/files_external/' : '/files_external/';
+		$path = is_null($this->uid) ? '/files_external/' : '/' . $this->uid . '/files_external/';
 
 		return $path;
 	}
diff --git a/lib/private/server.php b/lib/private/server.php
index c98f77c647..672245c352 100644
--- a/lib/private/server.php
+++ b/lib/private/server.php
@@ -249,7 +249,9 @@ class Server extends SimpleContainer implements IServerContainer {
 		});
 		$this->registerService('HTTPHelper', function (Server $c) {
 			$config = $c->getConfig();
-			return new HTTPHelper($config, new \OC\Security\CertificateManager($c->getUserSession()->getUser()));
+			$user = $c->getUserSession()->getUser();
+			$uid = $user ? $user->getUID() : null;
+			return new HTTPHelper($config, new \OC\Security\CertificateManager($uid));
 		});
 		$this->registerService('EventLogger', function (Server $c) {
 			if (defined('DEBUG') and DEBUG) {
@@ -631,18 +633,19 @@ class Server extends SimpleContainer implements IServerContainer {
 	/**
 	 * Get the certificate manager for the user
 	 *
-	 * @param \OCP\IUser $user (optional) if not specified the current loggedin user is used
+	 * @param string $uid (optional) if not specified the current loggedin user is used
 	 * @return \OCP\ICertificateManager
 	 */
-	function getCertificateManager($user = null) {
-		if (is_null($user)) {
+	function getCertificateManager($uid = null) {
+		if (is_null($uid)) {
 			$userSession = $this->getUserSession();
 			$user = $userSession->getUser();
 			if (is_null($user)) {
 				return null;
 			}
+			$uid = $user->getUID();
 		}
-		return new CertificateManager($user);
+		return new CertificateManager($uid);
 	}
 
 	/**
diff --git a/tests/lib/security/certificatemanager.php b/tests/lib/security/certificatemanager.php
index cff6932b67..83980a6755 100644
--- a/tests/lib/security/certificatemanager.php
+++ b/tests/lib/security/certificatemanager.php
@@ -28,9 +28,7 @@ class CertificateManagerTest extends \Test\TestCase {
 		\OC\Files\Filesystem::tearDown();
 		\OC_Util::setupFS($this->username);
 
-		$this->user = \OC::$server->getUserManager()->get($this->username);
-
-		$this->certificateManager = new CertificateManager($this->user);
+		$this->certificateManager = new CertificateManager($this->username);
 	}
 
 	protected function tearDown() {
@@ -84,7 +82,7 @@ class CertificateManagerTest extends \Test\TestCase {
 	}
 
 	function testGetCertificateBundle() {
-		$this->assertSame($this->user->getHome().'/files_external/rootcerts.crt', $this->certificateManager->getCertificateBundle());
+		$this->assertSame('/' . $this->username . '/files_external/rootcerts.crt', $this->certificateManager->getCertificateBundle());
 	}
 
 }
\ No newline at end of file