diff --git a/lib/files/filesystem.php b/lib/files/filesystem.php
index 8c8e80c1be4bb7ebabcdec847fb11aa9b0953ab1..09732e67ac618d2e2c1dd11bee8e47f2814b9ccf 100644
--- a/lib/files/filesystem.php
+++ b/lib/files/filesystem.php
@@ -311,6 +311,7 @@ class Filesystem {
 	 */
 	static public function tearDown() {
 		self::clearMounts();
+		self::$defaultInstance = null;
 	}
 
 	/**
diff --git a/lib/files/mount.php b/lib/files/mount.php
index 59c98e9dcc8e651ca8b874408f6bd338a25bac27..0030d0ee7a637fc3607103d3ca719b58d669450c 100644
--- a/lib/files/mount.php
+++ b/lib/files/mount.php
@@ -136,6 +136,7 @@ class Mount {
 	 * @return Mount
 	 */
 	public static function find($path) {
+		\OC_Util::setupFS();
 		$path = self::formatPath($path);
 		if (isset(self::$mounts[$path])) {
 			return self::$mounts[$path];
@@ -163,6 +164,7 @@ class Mount {
 	 * @return Mount[]
 	 */
 	public static function findIn($path) {
+		\OC_Util::setupFS();
 		$path = self::formatPath($path);
 		$result = array();
 		$pathLength = strlen($path);
@@ -186,6 +188,7 @@ class Mount {
 	 * @return Mount[]
 	 */
 	public static function findByStorageId($id) {
+		\OC_Util::setupFS();
 		if (strlen($id) > 64) {
 			$id = md5($id);
 		}
diff --git a/tests/lib/files/cache/updater.php b/tests/lib/files/cache/updater.php
index aaf932c97feb88a086d4545e7c7b4bd44d348c70..dad3cd7e6503cf671375fd1049bc8b7cc3e3f9fa 100644
--- a/tests/lib/files/cache/updater.php
+++ b/tests/lib/files/cache/updater.php
@@ -42,14 +42,11 @@ class Updater extends \PHPUnit_Framework_TestCase {
 		$this->scanner->scan('');
 		$this->cache = $this->storage->getCache();
 
+		\OC\Files\Filesystem::tearDown();
 		if (!self::$user) {
-			if (!\OC\Files\Filesystem::getView()) {
-				self::$user = uniqid();
-				\OC\Files\Filesystem::init(self::$user, '/' . self::$user . '/files');
-			} else {
-				self::$user = \OC_User::getUser();
-			}
+			self::$user = uniqid();
 		}
+		\OC\Files\Filesystem::init(self::$user, '/' . self::$user . '/files');
 
 		Filesystem::clearMounts();
 		Filesystem::mount($this->storage, array(), '/' . self::$user . '/files');