diff --git a/lib/files/mapper.php b/lib/files/mapper.php
index 71b665e49b..2d29a8532b 100644
--- a/lib/files/mapper.php
+++ b/lib/files/mapper.php
@@ -117,6 +117,9 @@ class Mapper
 		$query = \OC_DB::prepare('SELECT * FROM `*PREFIX*file_map` WHERE `logic_path_hash` = ?');
 		$result = $query->execute(array(md5($logicPath)));
 		$result = $result->fetchRow();
+		if ($result === false) {
+			return null;
+		}
 
 		return $result['physic_path'];
 	}
@@ -160,11 +163,16 @@ class Mapper
 		$sluggedElements = array();
 
 		// skip slugging the drive letter on windows - TODO: test if local path
-		if (strpos(strtolower(php_uname('s')), 'win') !== false) {
+		if (\OC_Util::runningOnWindows()) {
 			$sluggedElements[]= $pathElements[0];
 			array_shift($pathElements);
 		}
 		foreach ($pathElements as $pathElement) {
+			// remove empty elements
+			if (empty($pathElement)) {
+				continue;
+			}
+
 			// TODO: remove file ext before slugify on last element
 			$sluggedElements[] = self::slugify($pathElement);
 		}
@@ -177,6 +185,12 @@ class Mapper
 			array_pop($sluggedElements);
 			array_push($sluggedElements, $last.'-'.$index);
 		}
+
+		// on non-windows systems add the leading / if necessary
+		if (!\OC_Util::runningOnWindows() and $path[0] === '/') {
+			return DIRECTORY_SEPARATOR.implode(DIRECTORY_SEPARATOR, $sluggedElements);
+		}
+
 		return implode(DIRECTORY_SEPARATOR, $sluggedElements);
 	}
 
diff --git a/lib/files/storage/local.php b/lib/files/storage/local.php
index 9fe0113586..aaa3c0fab4 100644
--- a/lib/files/storage/local.php
+++ b/lib/files/storage/local.php
@@ -9,7 +9,9 @@
 namespace OC\Files\Storage;
 
 if (\OC_Util::runningOnWindows()) {
-	require_once 'mappedlocal.php';
+	class Local extends MappedLocal {
+
+	}
 } else {
 
 /**
diff --git a/lib/files/storage/mappedlocal.php b/lib/files/storage/mappedlocal.php
index 80dd79bc41..218465d8ee 100644
--- a/lib/files/storage/mappedlocal.php
+++ b/lib/files/storage/mappedlocal.php
@@ -10,7 +10,7 @@ namespace OC\Files\Storage;
 /**
  * for local filestore, we only have to map the paths
  */
-class Local extends \OC\Files\Storage\Common{
+class MappedLocal extends \OC\Files\Storage\Common{
 	protected $datadir;
 	private $mapper;
 
@@ -329,6 +329,9 @@ class Local extends \OC\Files\Storage\Common{
 		if(strpos($path, '/') === 0) {
 			$path = substr($path, 1);
 		}
+		if ($path === false) {
+			return '';
+		}
 
 		return $path;
 	}
diff --git a/tests/lib/files/storage/mappedlocal.php b/tests/lib/files/storage/mappedlocal.php
new file mode 100644
index 0000000000..b483f3a195
--- /dev/null
+++ b/tests/lib/files/storage/mappedlocal.php
@@ -0,0 +1,40 @@
+<?php
+/**
+* ownCloud
+*
+* @author Robin Appelman
+* @copyright 2012 Robin Appelman icewind@owncloud.com
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+* License as published by the Free Software Foundation; either
+* version 3 of the License, or any later version.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
+*
+* You should have received a copy of the GNU Affero General Public
+* License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+*
+*/
+
+namespace Test\Files\Storage;
+
+class MappedLocal extends Storage {
+	/**
+	 * @var string tmpDir
+	 */
+	private $tmpDir;
+	public function setUp() {
+		$this->tmpDir=\OC_Helper::tmpFolder();
+		$this->instance=new \OC\Files\Storage\MappedLocal(array('datadir'=>$this->tmpDir));
+	}
+
+	public function tearDown() {
+		\OC_Helper::rmdirr($this->tmpDir);
+		unset($this->instance);
+	}
+}
+