diff --git a/apps/files_external/lib/config.php b/apps/files_external/lib/config.php
index d7286c52c02cbc7d161b75a4177a116ccb485eb3..3bb512493d8d147d124c6ef90f5b20e016643c5a 100755
--- a/apps/files_external/lib/config.php
+++ b/apps/files_external/lib/config.php
@@ -122,7 +122,7 @@ class OC_Mount_Config {
 				foreach ($mounts as $mountPoint => $mount) {
 					// Update old classes to new namespace
 					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
-						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15, strlen($mount['class']) - 15);
+						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
 					}
 					// Remove '/$user/files/' from mount point
 					$mountPoint = substr($mountPoint, 13);
@@ -145,7 +145,7 @@ class OC_Mount_Config {
 				foreach ($mounts as $mountPoint => $mount) {
 					// Update old classes to new namespace
 					if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
-						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15, strlen($mount['class']) - 15);
+						$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
 					}
 					// Remove '/$user/files/' from mount point
 					$mountPoint = substr($mountPoint, 13);
@@ -179,7 +179,7 @@ class OC_Mount_Config {
 			foreach ($mountPoints[self::MOUNT_TYPE_USER][$uid] as $mountPoint => $mount) {
 				// Update old classes to new namespace
 				if (strpos($mount['class'], 'OC_Filestorage_') !== false) {
-					$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15, strlen($mount['class']) - 15);
+					$mount['class'] = '\OC\Files\Storage\\'.substr($mount['class'], 15);
 				}
 				// Remove '/uid/files/' from mount point
 				$personal[substr($mountPoint, strlen($uid) + 8)] = array('class' => $mount['class'],
diff --git a/lib/files/filesystem.php b/lib/files/filesystem.php
index b9fd6a03762eadb4bfb1cfdf2f25444964947367..d9487bde806e333c5d08709129a40b50ad26c6ca 100644
--- a/lib/files/filesystem.php
+++ b/lib/files/filesystem.php
@@ -366,7 +366,7 @@ class Filesystem {
 		}
 		// Update old classes to new namespace
 		if (strpos($class, 'OC_Filestorage_') !== false) {
-			$class = '\OC\Files\Storage\\'.substr($class, 15, strlen($class) - 15);
+			$class = '\OC\Files\Storage\\'.substr($class, 15);
 		}
 		if ($class instanceof \OC\Files\Storage\Storage) {
 			self::$mounts[$mountpoint] = array('class' => get_class($class), 'arguments' => $arguments);