diff --git a/apps/files_sharing/tests/testcase.php b/apps/files_sharing/tests/testcase.php
index 39e34f3ba2..cbf324df55 100644
--- a/apps/files_sharing/tests/testcase.php
+++ b/apps/files_sharing/tests/testcase.php
@@ -94,13 +94,13 @@ abstract class TestCase extends \Test\TestCase {
 	protected function setUp() {
 		parent::setUp();
 
-		$this->assertFalse(\OC_App::isEnabled('files_encryption'));
-
 		//login as user1
 		self::loginHelper(self::TEST_FILES_SHARING_API_USER1);
 
 		$this->data = 'foobar';
 		$this->view = new \OC\Files\View('/' . self::TEST_FILES_SHARING_API_USER1 . '/files');
+
+		$this->assertFalse(\OC_App::isEnabled('files_encryption'));
 	}
 
 	protected function tearDown() {
diff --git a/lib/private/app.php b/lib/private/app.php
index 962c5fe368..2b6c675488 100644
--- a/lib/private/app.php
+++ b/lib/private/app.php
@@ -62,6 +62,7 @@ class OC_App {
 
 	/**
 	 * clean the appId
+	 *
 	 * @param string|boolean $app AppId that needs to be cleaned
 	 * @return string
 	 */
@@ -71,6 +72,7 @@ class OC_App {
 
 	/**
 	 * loads all apps
+	 *
 	 * @param array $types
 	 * @return bool
 	 *
@@ -216,7 +218,7 @@ class OC_App {
 	 * @param bool $forceRefresh whether to refresh the cache
 	 * @param bool $all whether to return apps for all users, not only the
 	 * currently logged in one
-	 * @return array
+	 * @return string[]
 	 */
 	public static function getEnabledApps($forceRefresh = false, $all = false) {
 		if (!OC_Config::getValue('installed', false)) {
@@ -224,52 +226,29 @@ class OC_App {
 		}
 		// in incognito mode or when logged out, $user will be false,
 		// which is also the case during an upgrade
-		$user = null;
-		if (!$all) {
-			$user = \OC_User::getUser();
+		$appManager = \OC::$server->getAppManager();
+		if ($all) {
+			$user = null;
+		} else {
+			$user = \OC::$server->getUserSession()->getUser();
 		}
-		if (is_string($user) && !$forceRefresh && !empty(self::$enabledAppsCache)) {
-			return self::$enabledAppsCache;
-		}
-		$apps = array();
-		$appConfig = \OC::$server->getAppConfig();
-		$appStatus = $appConfig->getValues(false, 'enabled');
-		foreach ($appStatus as $app => $enabled) {
-			if ($app === 'files') {
-				continue;
-			}
-			if ($enabled === 'yes') {
-				$apps[] = $app;
-			} else if ($enabled !== 'no') {
-				$groups = json_decode($enabled);
-				if (is_array($groups)) {
-					if (is_string($user)) {
-						foreach ($groups as $group) {
-							if (\OC_Group::inGroup($user, $group)) {
-								$apps[] = $app;
-								break;
-							}
-						}
-					} else {
-						// global, consider app as enabled
-						$apps[] = $app;
-					}
-				}
-			}
+
+		if (is_null($user)) {
+			$apps = $appManager->getInstalledApps();
+		} else {
+			$apps = $appManager->getEnabledAppsForUser($user);
 		}
+		$apps = array_filter($apps, function ($app) {
+			return $app !== 'files';//we add this manually
+		});
 		sort($apps);
 		array_unshift($apps, 'files');
-		// Only cache the app list, when the user is logged in.
-		// Otherwise we cache the list with disabled apps, although
-		// the apps are enabled for the user after he logged in.
-		if ($user) {
-			self::$enabledAppsCache = $apps;
-		}
 		return $apps;
 	}
 
 	/**
 	 * checks whether or not an app is enabled
+	 *
 	 * @param string $app app
 	 * @return bool
 	 *
@@ -279,12 +258,12 @@ class OC_App {
 		if ('files' == $app) {
 			return true;
 		}
-		$enabledApps = self::getEnabledApps();
-		return in_array($app, $enabledApps);
+		return \OC::$server->getAppManager()->isEnabledForUser($app);
 	}
 
 	/**
 	 * enables an app
+	 *
 	 * @param mixed $app app
 	 * @param array $groups (optional) when set, only these groups will have access to the app
 	 * @throws \Exception
@@ -298,10 +277,11 @@ class OC_App {
 			$app = self::installApp($app);
 		}
 
+		$appManager = \OC::$server->getAppManager();
 		if (!is_null($groups)) {
-			OC_Appconfig::setValue($app, 'enabled', json_encode($groups));
-		}else{
-			OC_Appconfig::setValue($app, 'enabled', 'yes');
+			$appManager->enableAppForGroups($app, $groups);
+		} else {
+			$appManager->enableApp($app);
 		}
 	}
 
@@ -310,13 +290,13 @@ class OC_App {
 	 * @return int
 	 */
 	public static function downloadApp($app) {
-		$appData=OC_OCSClient::getApplication($app);
-		$download=OC_OCSClient::getApplicationDownload($app, 1);
-		if(isset($download['downloadlink']) and $download['downloadlink']!='') {
+		$appData = OC_OCSClient::getApplication($app);
+		$download = OC_OCSClient::getApplicationDownload($app, 1);
+		if (isset($download['downloadlink']) and $download['downloadlink'] != '') {
 			// Replace spaces in download link without encoding entire URL
 			$download['downloadlink'] = str_replace(' ', '%20', $download['downloadlink']);
-			$info = array('source'=>'http', 'href'=>$download['downloadlink'], 'appdata'=>$appData);
-			$app=OC_Installer::installApp($info);
+			$info = array('source' => 'http', 'href' => $download['downloadlink'], 'appdata' => $appData);
+			$app = OC_Installer::installApp($info);
 		}
 		return $app;
 	}
@@ -335,6 +315,7 @@ class OC_App {
 
 	/**
 	 * This function set an app as disabled in appconfig.
+	 *
 	 * @param string $app app
 	 * @throws Exception
 	 */
@@ -345,11 +326,13 @@ class OC_App {
 		self::$enabledAppsCache = array(); // flush
 		// check if app is a shipped app or not. if not delete
 		\OC_Hook::emit('OC_App', 'pre_disable', array('app' => $app));
-		OC_Appconfig::setValue($app, 'enabled', 'no' );
+		$appManager = \OC::$server->getAppManager();
+		$appManager->disableApp($app);
 	}
 
 	/**
 	 * adds an entry to the navigation
+	 *
 	 * @param array $data array containing the data
 	 * @return bool
 	 *
@@ -372,6 +355,7 @@ class OC_App {
 
 	/**
 	 * marks a navigation entry as active
+	 *
 	 * @param string $id id of the entry
 	 * @return bool
 	 *
@@ -386,6 +370,7 @@ class OC_App {
 
 	/**
 	 * Get the navigation entries for the $app
+	 *
 	 * @param string $app app
 	 * @return array an array of the $data added with addNavigationEntry
 	 *
@@ -402,6 +387,7 @@ class OC_App {
 
 	/**
 	 * gets the active Menu entry
+	 *
 	 * @return string id or empty string
 	 *
 	 * This function returns the id of the active navigation entry (set by
@@ -413,6 +399,7 @@ class OC_App {
 
 	/**
 	 * Returns the Settings Navigation
+	 *
 	 * @return string
 	 *
 	 * This function returns an array containing all settings pages added. The
@@ -517,6 +504,7 @@ class OC_App {
 
 	/**
 	 * search for an app in all app-directories
+	 *
 	 * @param $appId
 	 * @return mixed (bool|string)
 	 */
@@ -528,21 +516,21 @@ class OC_App {
 		}
 
 		$possibleApps = array();
-		foreach(OC::$APPSROOTS as $dir) {
-			if(file_exists($dir['path'] . '/' . $appId)) {
+		foreach (OC::$APPSROOTS as $dir) {
+			if (file_exists($dir['path'] . '/' . $appId)) {
 				$possibleApps[] = $dir;
 			}
 		}
 
 		if (empty($possibleApps)) {
 			return false;
-		} elseif(count($possibleApps) === 1) {
+		} elseif (count($possibleApps) === 1) {
 			$dir = array_shift($possibleApps);
 			$app_dir[$appId] = $dir;
 			return $dir;
 		} else {
 			$versionToLoad = array();
-			foreach($possibleApps as $possibleApp) {
+			foreach ($possibleApps as $possibleApp) {
 				$version = self::getAppVersionByPath($possibleApp['path']);
 				if (empty($versionToLoad) || version_compare($version, $versionToLoad['version'], '>')) {
 					$versionToLoad = array(
@@ -617,15 +605,16 @@ class OC_App {
 
 	/**
 	 * get app's version based on it's path
+	 *
 	 * @param string $path
 	 * @return string
 	 */
 	public static function getAppVersionByPath($path) {
 		$versionFile = $path . '/appinfo/version';
 		$infoFile = $path . '/appinfo/info.xml';
-		if(is_file($versionFile)) {
+		if (is_file($versionFile)) {
 			return trim(file_get_contents($versionFile));
-		}else{
+		} else {
 			$appData = self::getAppInfo($infoFile, true);
 			return isset($appData['version']) ? $appData['version'] : '';
 		}
@@ -653,7 +642,7 @@ class OC_App {
 		$parser = new \OC\App\InfoParser(\OC::$server->getHTTPHelper(), \OC::$server->getURLGenerator());
 		$data = $parser->parse($file);
 
-		if(is_array($data)) {
+		if (is_array($data)) {
 			$data = OC_App::parseAppInfo($data);
 		}
 
@@ -664,6 +653,7 @@ class OC_App {
 
 	/**
 	 * Returns the navigation
+	 *
 	 * @return array
 	 *
 	 * This function returns an array containing all entries added. The
@@ -755,6 +745,7 @@ class OC_App {
 
 	/**
 	 * get a list of all apps in the apps folder
+	 *
 	 * @return array an array of app names (string IDs)
 	 * @todo: change the name of this method to getInstalledApps, which is more accurate
 	 */
@@ -788,6 +779,7 @@ class OC_App {
 
 	/**
 	 * Lists all apps, this is used in apps.php
+	 *
 	 * @return array
 	 */
 	public static function listAllApps($onlyLocal = false) {
@@ -814,7 +806,7 @@ class OC_App {
 				$info['groups'] = null;
 				if ($enabled === 'yes') {
 					$active = true;
-				} else if($enabled === 'no') {
+				} else if ($enabled === 'no') {
 					$active = false;
 				} else {
 					$active = true;
@@ -823,7 +815,7 @@ class OC_App {
 
 				$info['active'] = $active;
 
-				if(isset($info['shipped']) and ($info['shipped'] == 'true')) {
+				if (isset($info['shipped']) and ($info['shipped'] == 'true')) {
 					$info['internal'] = true;
 					$info['internallabel'] = (string)$l->t('Recommended');
 					$info['internalclass'] = 'recommendedapp';
@@ -835,9 +827,9 @@ class OC_App {
 
 				$info['update'] = OC_Installer::isUpdateAvailable($app);
 
-				$appIcon = self::getAppPath($app) . '/img/' . $app.'.svg';
+				$appIcon = self::getAppPath($app) . '/img/' . $app . '.svg';
 				if (file_exists($appIcon)) {
-					$info['preview'] = OC_Helper::imagePath($app, $app.'.svg');
+					$info['preview'] = OC_Helper::imagePath($app, $app . '.svg');
 					$info['previewAsIcon'] = true;
 				} else {
 					$appIcon = self::getAppPath($app) . '/img/app.svg';
@@ -861,7 +853,8 @@ class OC_App {
 				foreach ($remoteApps AS $key => $remote) {
 					if ($app['name'] === $remote['name'] ||
 						(isset($app['ocsid']) &&
-						$app['ocsid'] ===  $remote['id'])) {
+							$app['ocsid'] === $remote['id'])
+					) {
 						unset($remoteApps[$key]);
 					}
 				}
@@ -904,6 +897,7 @@ class OC_App {
 
 	/**
 	 * get a list of all apps on apps.owncloud.com
+	 * 
 	 * @return array|false multi-dimensional array of apps.
 	 *     Keys: id, name, type, typename, personid, license, detailpage, preview, changed, description
 	 */
@@ -983,7 +977,7 @@ class OC_App {
 		foreach ($apps as $app) {
 			// check if the app is compatible with this version of ownCloud
 			$info = OC_App::getAppInfo($app);
-			if(!self::isAppCompatible($version, $info)) {
+			if (!self::isAppCompatible($version, $info)) {
 				OC_Log::write('core',
 					'App "' . $info['name'] . '" (' . $app . ') can\'t be used because it is'
 					. ' not compatible with this version of ownCloud',
@@ -1030,11 +1024,11 @@ class OC_App {
 	 * and "requiremax" => 6 and it will still match ownCloud 6.0.3.
 	 *
 	 * @param string $ocVersion ownCloud version to check against
-	 * @param array  $appInfo app info (from xml)
+	 * @param array $appInfo app info (from xml)
 	 *
 	 * @return boolean true if compatible, otherwise false
 	 */
-	public static function isAppCompatible($ocVersion, $appInfo){
+	public static function isAppCompatible($ocVersion, $appInfo) {
 		$requireMin = '';
 		$requireMax = '';
 		if (isset($appInfo['dependencies']['owncloud']['@attributes']['min-version'])) {
@@ -1104,25 +1098,25 @@ class OC_App {
 	public static function installApp($app) {
 		$l = \OC::$server->getL10N('core');
 		$config = \OC::$server->getConfig();
-		$appData=OC_OCSClient::getApplication($app);
+		$appData = OC_OCSClient::getApplication($app);
 
 		// check if app is a shipped app or not. OCS apps have an integer as id, shipped apps use a string
-		if(!is_numeric($app)) {
-			$shippedVersion=self::getAppVersion($app);
-			if($appData && version_compare($shippedVersion, $appData['version'], '<')) {
+		if (!is_numeric($app)) {
+			$shippedVersion = self::getAppVersion($app);
+			if ($appData && version_compare($shippedVersion, $appData['version'], '<')) {
 				$app = self::downloadApp($app);
 			} else {
 				$app = OC_Installer::installShippedApp($app);
 			}
-		}else{
+		} else {
 			$app = self::downloadApp($app);
 		}
 
-		if($app!==false) {
+		if ($app !== false) {
 			// check if the app is compatible with this version of ownCloud
 			$info = self::getAppInfo($app);
-			$version=OC_Util::getVersion();
-			if(!self::isAppCompatible($version, $info)) {
+			$version = OC_Util::getVersion();
+			if (!self::isAppCompatible($version, $info)) {
 				throw new \Exception(
 					$l->t('App \"%s\" can\'t be installed because it is not compatible with this version of ownCloud.',
 						array($info['name'])
@@ -1133,7 +1127,7 @@ class OC_App {
 			// check for required dependencies
 			$dependencyAnalyzer = new DependencyAnalyzer(new Platform($config), $l);
 			$missing = $dependencyAnalyzer->analyze($app);
-			if(!empty($missing)) {
+			if (!empty($missing)) {
 				$missingMsg = join(PHP_EOL, $missing);
 				throw new \Exception(
 					$l->t('App \"%s\" cannot be installed because the following dependencies are not fulfilled: %s',
@@ -1143,11 +1137,11 @@ class OC_App {
 			}
 
 			$config->setAppValue($app, 'enabled', 'yes');
-			if(isset($appData['id'])) {
-				$config->setAppValue($app, 'ocsid', $appData['id'] );
+			if (isset($appData['id'])) {
+				$config->setAppValue($app, 'ocsid', $appData['id']);
 			}
 			\OC_Hook::emit('OC_App', 'post_enable', array('app' => $app));
-		}else{
+		} else {
 			throw new \Exception($l->t("No app name specified"));
 		}
 
@@ -1225,7 +1219,7 @@ class OC_App {
 
 		// just modify the description if it is available
 		// otherwise this will create a $data element with an empty 'description'
-		if(isset($data['description'])) {
+		if (isset($data['description'])) {
 			// sometimes the description contains line breaks and they are then also
 			// shown in this way in the app management which isn't wanted as HTML
 			// manages line breaks itself
diff --git a/lib/private/app/appmanager.php b/lib/private/app/appmanager.php
index ec7e6c80c5..66a52935a2 100644
--- a/lib/private/app/appmanager.php
+++ b/lib/private/app/appmanager.php
@@ -24,6 +24,7 @@ namespace OC\App;
 use OCP\App\IAppManager;
 use OCP\IAppConfig;
 use OCP\IGroupManager;
+use OCP\IUser;
 use OCP\IUserSession;
 
 class AppManager implements IAppManager {
@@ -61,7 +62,7 @@ class AppManager implements IAppManager {
 	/**
 	 * @return string[] $appId => $enabled
 	 */
-	private function getInstalledApps() {
+	private function getInstalledAppsValues() {
 		if (!$this->installedAppsCache) {
 			$values = $this->appConfig->getValues(false, 'enabled');
 			$this->installedAppsCache = array_filter($values, function ($value) {
@@ -72,6 +73,29 @@ class AppManager implements IAppManager {
 		return $this->installedAppsCache;
 	}
 
+	/**
+	 * List all installed apps
+	 *
+	 * @return string[]
+	 */
+	public function getInstalledApps() {
+		return array_keys($this->getInstalledAppsValues());
+	}
+
+	/**
+	 * List all apps enabled for a user
+	 *
+	 * @param \OCP\IUser $user
+	 * @return string[]
+	 */
+	public function getEnabledAppsForUser(IUser $user) {
+		$apps = $this->getInstalledAppsValues();
+		$appsForUser = array_filter($apps, function ($enabled) use ($user) {
+			return $this->checkAppForUser($enabled, $user);
+		});
+		return array_keys($appsForUser);
+	}
+
 	/**
 	 * Check if an app is enabled for user
 	 *
@@ -83,28 +107,36 @@ class AppManager implements IAppManager {
 		if (is_null($user)) {
 			$user = $this->userSession->getUser();
 		}
-		$installedApps = $this->getInstalledApps();
+		$installedApps = $this->getInstalledAppsValues();
 		if (isset($installedApps[$appId])) {
-			$enabled = $installedApps[$appId];
-			if ($enabled === 'yes') {
-				return true;
-			} elseif (is_null($user)) {
-				return false;
-			} else {
-				$groupIds = json_decode($enabled);
-				$userGroups = $this->groupManager->getUserGroupIds($user);
-				foreach ($userGroups as $groupId) {
-					if (array_search($groupId, $groupIds) !== false) {
-						return true;
-					}
-				}
-				return false;
-			}
+			return $this->checkAppForUser($installedApps[$appId], $user);
 		} else {
 			return false;
 		}
 	}
 
+	/**
+	 * @param string $enabled
+	 * @param IUser $user
+	 * @return bool
+	 */
+	private function checkAppForUser($enabled, $user) {
+		if ($enabled === 'yes') {
+			return true;
+		} elseif (is_null($user)) {
+			return false;
+		} else {
+			$groupIds = json_decode($enabled);
+			$userGroups = $this->groupManager->getUserGroupIds($user);
+			foreach ($userGroups as $groupId) {
+				if (array_search($groupId, $groupIds) !== false) {
+					return true;
+				}
+			}
+			return false;
+		}
+	}
+
 	/**
 	 * Check if an app is installed in the instance
 	 *
@@ -112,7 +144,7 @@ class AppManager implements IAppManager {
 	 * @return bool
 	 */
 	public function isInstalled($appId) {
-		$installedApps = $this->getInstalledApps();
+		$installedApps = $this->getInstalledAppsValues();
 		return isset($installedApps[$appId]);
 	}
 
@@ -122,6 +154,7 @@ class AppManager implements IAppManager {
 	 * @param string $appId
 	 */
 	public function enableApp($appId) {
+		$this->installedAppsCache[$appId] = 'yes';
 		$this->appConfig->setValue($appId, 'enabled', 'yes');
 	}
 
@@ -136,6 +169,7 @@ class AppManager implements IAppManager {
 			/** @var \OCP\IGroup $group */
 			return $group->getGID();
 		}, $groups);
+		$this->installedAppsCache[$appId] = json_encode($groupIds);
 		$this->appConfig->setValue($appId, 'enabled', json_encode($groupIds));
 	}
 
@@ -146,9 +180,10 @@ class AppManager implements IAppManager {
 	 * @throws \Exception if app can't be disabled
 	 */
 	public function disableApp($appId) {
-		if($appId === 'files') {
+		if ($appId === 'files') {
 			throw new \Exception("files can't be disabled.");
 		}
+		unset($this->installedAppsCache[$appId]);
 		$this->appConfig->setValue($appId, 'enabled', 'no');
 	}
 }
diff --git a/lib/private/group/manager.php b/lib/private/group/manager.php
index dd5971f94b..29dc186089 100644
--- a/lib/private/group/manager.php
+++ b/lib/private/group/manager.php
@@ -236,16 +236,7 @@ class Manager extends PublicEmitter implements IGroupManager {
 	 * @return array with group ids
 	 */
 	public function getUserGroupIds($user) {
-		$groupIds = array();
-		$userId = $user->getUID();
-		if (isset($this->cachedUserGroups[$userId])) {
-			return array_keys($this->cachedUserGroups[$userId]);
-		} else {
-			foreach ($this->backends as $backend) {
-				$groupIds = array_merge($groupIds, $backend->getUserGroups($userId));
-			}
-		}
-		return $groupIds;
+		return array_keys($this->getUserGroups($user));
 	}
 
 	/**
diff --git a/lib/private/user.php b/lib/private/user.php
index 25b95f8608..5d3152247e 100644
--- a/lib/private/user.php
+++ b/lib/private/user.php
@@ -66,6 +66,7 @@ class OC_User {
 
 	/**
 	 * registers backend
+	 *
 	 * @param string $backend name of the backend
 	 * @deprecated Add classes by calling OC_User::useBackend() with a class instance instead
 	 * @return bool
@@ -79,6 +80,7 @@ class OC_User {
 
 	/**
 	 * gets available backends
+	 *
 	 * @deprecated
 	 * @return array an array of backends
 	 *
@@ -90,6 +92,7 @@ class OC_User {
 
 	/**
 	 * gets used backends
+	 *
 	 * @deprecated
 	 * @return array an array of backends
 	 *
@@ -101,6 +104,7 @@ class OC_User {
 
 	/**
 	 * Adds the backend to the list of used backends
+	 *
 	 * @param string|OC_User_Interface $backend default: database The backend to use for user management
 	 * @return bool
 	 *
@@ -173,6 +177,7 @@ class OC_User {
 
 	/**
 	 * Create a new user
+	 *
 	 * @param string $uid The username of the user to create
 	 * @param string $password The password of the new user
 	 * @throws Exception
@@ -190,6 +195,7 @@ class OC_User {
 
 	/**
 	 * delete a user
+	 *
 	 * @param string $uid The username of the user to delete
 	 * @return bool
 	 *
@@ -207,6 +213,7 @@ class OC_User {
 
 	/**
 	 * Try to login a user
+	 *
 	 * @param string $loginname The login name of the user to log in
 	 * @param string $password The password of the user
 	 * @return boolean|null
@@ -247,14 +254,14 @@ class OC_User {
 
 		$uid = $backend->getCurrentUserId();
 		$run = true;
-		OC_Hook::emit( "OC_User", "pre_login", array( "run" => &$run, "uid" => $uid ));
+		OC_Hook::emit("OC_User", "pre_login", array("run" => &$run, "uid" => $uid));
 
-		if($uid) {
+		if ($uid) {
 			self::setUserId($uid);
 			self::setDisplayName($uid);
 			self::getUserSession()->setLoginName($uid);
 
-			OC_Hook::emit( "OC_User", "post_login", array( "uid" => $uid, 'password'=>'' ));
+			OC_Hook::emit("OC_User", "post_login", array("uid" => $uid, 'password' => ''));
 			return true;
 		}
 		return false;
@@ -288,11 +295,18 @@ class OC_User {
 	 * Sets user id for session and triggers emit
 	 */
 	public static function setUserId($uid) {
-		\OC::$server->getSession()->set('user_id', $uid);
+		$userSession = \OC::$server->getUserSession();
+		$userManager = \OC::$server->getUserManager();
+		if ($user = $userManager->get($uid)) {
+			$userSession->setUser($user);
+		} else {
+			\OC::$server->getSession()->set('user_id', $uid);
+		}
 	}
 
 	/**
 	 * Sets user display name for session
+	 *
 	 * @param string $uid
 	 * @param null $displayName
 	 * @return bool Whether the display name could get set
@@ -322,13 +336,14 @@ class OC_User {
 	 * Tries to login the user with HTTP Basic Authentication
 	 */
 	public static function tryBasicAuthLogin() {
-		if(!empty($_SERVER['PHP_AUTH_USER']) && !empty($_SERVER['PHP_AUTH_PW'])) {
+		if (!empty($_SERVER['PHP_AUTH_USER']) && !empty($_SERVER['PHP_AUTH_PW'])) {
 			\OC_User::login($_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW']);
 		}
 	}
 
 	/**
 	 * Check if the user is logged in, considers also the HTTP basic credentials
+	 *
 	 * @return bool
 	 */
 	public static function isLoggedIn() {
@@ -341,6 +356,7 @@ class OC_User {
 
 	/**
 	 * set incognito mode, e.g. if a user wants to open a public link
+	 *
 	 * @param bool $status
 	 */
 	public static function setIncognitoMode($status) {
@@ -349,6 +365,7 @@ class OC_User {
 
 	/**
 	 * get incognito mode status
+	 *
 	 * @return bool
 	 */
 	public static function isIncognitoMode() {
@@ -373,6 +390,7 @@ class OC_User {
 
 	/**
 	 * Check if the user is an admin user
+	 *
 	 * @param string $uid uid of the admin
 	 * @return bool
 	 */
@@ -386,6 +404,7 @@ class OC_User {
 
 	/**
 	 * get the user id of the user currently logged in.
+	 *
 	 * @return string uid or false
 	 */
 	public static function getUser() {
@@ -399,6 +418,7 @@ class OC_User {
 
 	/**
 	 * get the display name of the user currently logged in.
+	 *
 	 * @param string $uid
 	 * @return string uid or false
 	 */
@@ -422,6 +442,7 @@ class OC_User {
 
 	/**
 	 * Autogenerate a password
+	 *
 	 * @return string
 	 *
 	 * generates a password
@@ -432,6 +453,7 @@ class OC_User {
 
 	/**
 	 * Set password
+	 *
 	 * @param string $uid The username
 	 * @param string $password The new password
 	 * @param string $recoveryPassword for the encryption app to reset encryption keys
@@ -450,6 +472,7 @@ class OC_User {
 
 	/**
 	 * Check whether user can change his avatar
+	 *
 	 * @param string $uid The username
 	 * @return bool
 	 *
@@ -466,6 +489,7 @@ class OC_User {
 
 	/**
 	 * Check whether user can change his password
+	 *
 	 * @param string $uid The username
 	 * @return bool
 	 *
@@ -482,6 +506,7 @@ class OC_User {
 
 	/**
 	 * Check whether user can change his display name
+	 *
 	 * @param string $uid The username
 	 * @return bool
 	 *
@@ -498,6 +523,7 @@ class OC_User {
 
 	/**
 	 * Check if the password is correct
+	 *
 	 * @param string $uid The username
 	 * @param string $password The password
 	 * @return string|false user id a string on success, false otherwise
@@ -532,6 +558,7 @@ class OC_User {
 
 	/**
 	 * Get a list of all users
+	 *
 	 * @return array an array of all uids
 	 *
 	 * Get a list of all users.
@@ -550,6 +577,7 @@ class OC_User {
 
 	/**
 	 * Get a list of all users display name
+	 *
 	 * @param string $search
 	 * @param int $limit
 	 * @param int $offset
@@ -569,6 +597,7 @@ class OC_User {
 
 	/**
 	 * check if a user exists
+	 *
 	 * @param string $uid the username
 	 * @return boolean
 	 */
@@ -617,6 +646,7 @@ class OC_User {
 
 	/**
 	 * Set cookie value to use in next page load
+	 *
 	 * @param string $username username to be set
 	 * @param string $token
 	 */
@@ -633,6 +663,7 @@ class OC_User {
 
 	/**
 	 * Returns the first active backend from self::$_usedBackends.
+	 *
 	 * @return OCP\Authentication\IApacheBackend|null if no backend active, otherwise OCP\Authentication\IApacheBackend
 	 */
 	private static function findFirstActiveUsedBackend() {
diff --git a/lib/private/util.php b/lib/private/util.php
index a839b10418..37e68df9a7 100644
--- a/lib/private/util.php
+++ b/lib/private/util.php
@@ -63,6 +63,10 @@ class OC_Util {
 	private static $rootMounted = false;
 	private static $fsSetup = false;
 
+	protected static function getAppManager() {
+		return \OC::$server->getAppManager();
+	}
+
 	private static function initLocalStorageRootFS() {
 		// mount local file backend as root
 		$configDataDirectory = OC_Config::getValue("datadirectory", OC::$SERVERROOT . "/data");
@@ -1010,7 +1014,7 @@ class OC_Util {
 				// find the first app that is enabled for the current user
 				foreach ($defaultApps as $defaultApp) {
 					$defaultApp = OC_App::cleanAppId(strip_tags($defaultApp));
-					if (OC_App::isEnabled($defaultApp)) {
+					if (static::getAppManager()->isEnabledForUser($defaultApp)) {
 						$appId = $defaultApp;
 						break;
 					}
diff --git a/lib/public/app/iappmanager.php b/lib/public/app/iappmanager.php
index a2f1c9c660..54c9a35270 100644
--- a/lib/public/app/iappmanager.php
+++ b/lib/public/app/iappmanager.php
@@ -20,6 +20,8 @@
  */
 namespace OCP\App;
 
+use OCP\IUser;
+
 interface IAppManager {
 	/**
 	 * Check if an app is enabled for user
@@ -59,4 +61,19 @@ interface IAppManager {
 	 * @param string $appId
 	 */
 	public function disableApp($appId);
+
+	/**
+	 * List all apps enabled for a user
+	 *
+	 * @param \OCP\IUser $user
+	 * @return string[]
+	 */
+	public function getEnabledAppsForUser(IUser $user);
+
+	/**
+	 * List all installed apps
+	 *
+	 * @return string[]
+	 */
+	public function getInstalledApps();
 }
diff --git a/tests/lib/app.php b/tests/lib/app.php
index 0c0eb28b3b..86a407c1a9 100644
--- a/tests/lib/app.php
+++ b/tests/lib/app.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * Copyright (c) 2012 Bernhard Posselt <dev@bernhard-posselt.com>
  * Copyright (c) 2014 Vincent Petry <pvince81@owncloud.com>
@@ -6,11 +7,8 @@
  * later.
  * See the COPYING-README file.
  */
-
 class Test_App extends \Test\TestCase {
 
-	private $oldAppConfigService;
-
 	const TEST_USER1 = 'user1';
 	const TEST_USER2 = 'user2';
 	const TEST_USER3 = 'user3';
@@ -398,10 +396,9 @@ class Test_App extends \Test\TestCase {
 					'appforgroup12' => '["group2","group1"]',
 				)
 			)
-		);
+			);
 
 		$apps = \OC_App::getEnabledApps(true, $forceAll);
-		$this->assertEquals($expectedApps, $apps);
 
 		$this->restoreAppConfig();
 		\OC_User::setUserId(null);
@@ -412,6 +409,8 @@ class Test_App extends \Test\TestCase {
 
 		$group1->delete();
 		$group2->delete();
+
+		$this->assertEquals($expectedApps, $apps);
 	}
 
 	/**
@@ -432,7 +431,7 @@ class Test_App extends \Test\TestCase {
 					'app2' => 'no',
 				)
 			)
-		);
+			);
 
 		$apps = \OC_App::getEnabledApps(true);
 		$this->assertEquals(array('files', 'app3'), $apps);
@@ -447,30 +446,6 @@ class Test_App extends \Test\TestCase {
 		$user1->delete();
 	}
 
-	/**
-	 * Tests that the apps list is re-requested (not cached) when
-	 * no user is set.
-	 */
-	public function testEnabledAppsNoCache() {
-		$this->setupAppConfigMock()->expects($this->exactly(2))
-			->method('getValues')
-			->will($this->returnValue(
-				array(
-					'app3' => 'yes',
-					'app2' => 'no',
-				)
-			)
-		);
-
-		$apps = \OC_App::getEnabledApps(true);
-		$this->assertEquals(array('files', 'app3'), $apps);
-
-		// mock should be called again here
-		$apps = \OC_App::getEnabledApps(false);
-		$this->assertEquals(array('files', 'app3'), $apps);
-
-		$this->restoreAppConfig();
-	}
 
 	private function setupAppConfigMock() {
 		$appConfig = $this->getMock(
@@ -487,22 +462,27 @@ class Test_App extends \Test\TestCase {
 
 	/**
 	 * Register an app config mock for testing purposes.
+	 *
 	 * @param $appConfig app config mock
 	 */
 	private function registerAppConfig($appConfig) {
-		$this->oldAppConfigService = \OC::$server->query('AppConfig');
 		\OC::$server->registerService('AppConfig', function ($c) use ($appConfig) {
 			return $appConfig;
 		});
+		\OC::$server->registerService('AppManager', function (\OC\Server $c) use ($appConfig) {
+			return new \OC\App\AppManager($c->getUserSession(), $appConfig, $c->getGroupManager());
+		});
 	}
 
 	/**
 	 * Restore the original app config service.
 	 */
 	private function restoreAppConfig() {
-		$oldService = $this->oldAppConfigService;
-		\OC::$server->registerService('AppConfig', function ($c) use ($oldService){
-			return $oldService;
+		\OC::$server->registerService('AppConfig', function ($c) {
+			return new \OC\AppConfig(\OC_DB::getConnection());
+		});
+		\OC::$server->registerService('AppManager', function (\OC\Server $c) {
+			return new \OC\App\AppManager($c->getUserSession(), $c->getAppConfig(), $c->getGroupManager());
 		});
 
 		// Remove the cache of the mocked apps list with a forceRefresh
diff --git a/tests/lib/app/manager.php b/tests/lib/app/manager.php
index 4c0555b501..cb41f73746 100644
--- a/tests/lib/app/manager.php
+++ b/tests/lib/app/manager.php
@@ -192,4 +192,36 @@ class Manager extends \PHPUnit_Framework_TestCase {
 		$appConfig->setValue('test', 'enabled', '["foo"]');
 		$this->assertTrue($manager->isEnabledForUser('test'));
 	}
+
+	public function testGetInstalledApps() {
+		$userSession = $this->getMock('\OCP\IUserSession');
+		$groupManager = $this->getMock('\OCP\IGroupManager');
+
+		$appConfig = $this->getAppConfig();
+		$manager = new \OC\App\AppManager($userSession, $appConfig, $groupManager);
+		$appConfig->setValue('test1', 'enabled', 'yes');
+		$appConfig->setValue('test2', 'enabled', 'no');
+		$appConfig->setValue('test3', 'enabled', '["foo"]');
+		$this->assertEquals(['test1', 'test3'], $manager->getInstalledApps());
+	}
+
+	public function testGetAppsForUser() {
+		$userSession = $this->getMock('\OCP\IUserSession');
+		$groupManager = $this->getMock('\OCP\IGroupManager');
+
+		$user = new User('user1', null);
+
+		$groupManager->expects($this->any())
+			->method('getUserGroupIds')
+			->with($user)
+			->will($this->returnValue(array('foo', 'bar')));
+
+		$appConfig = $this->getAppConfig();
+		$manager = new \OC\App\AppManager($userSession, $appConfig, $groupManager);
+		$appConfig->setValue('test1', 'enabled', 'yes');
+		$appConfig->setValue('test2', 'enabled', 'no');
+		$appConfig->setValue('test3', 'enabled', '["foo"]');
+		$appConfig->setValue('test4', 'enabled', '["asd"]');
+		$this->assertEquals(['test1', 'test3'], $manager->getEnabledAppsForUser($user));
+	}
 }
diff --git a/tests/lib/appconfig.php b/tests/lib/appconfig.php
index 188721ff92..ead5b85927 100644
--- a/tests/lib/appconfig.php
+++ b/tests/lib/appconfig.php
@@ -11,6 +11,12 @@ class Test_Appconfig extends \Test\TestCase {
 	public static function setUpBeforeClass() {
 		parent::setUpBeforeClass();
 
+		$query = \OC_DB::prepare('DELETE FROM `*PREFIX*appconfig` WHERE `appid` = ?');
+		$query->execute(array('testapp'));
+		$query->execute(array('someapp'));
+		$query->execute(array('123456'));
+		$query->execute(array('anotherapp'));
+
 		$query = \OC_DB::prepare('INSERT INTO `*PREFIX*appconfig` VALUES (?, ?, ?)');
 
 		$query->execute(array('testapp', 'enabled', 'true'));
diff --git a/tests/lib/util.php b/tests/lib/util.php
index 25c9e31bea..6870b21807 100644
--- a/tests/lib/util.php
+++ b/tests/lib/util.php
@@ -1,11 +1,11 @@
 <?php
+
 /**
  * Copyright (c) 2012 Lukas Reschke <lukas@statuscode.ch>
  * This file is licensed under the Affero General Public License version 3 or
  * later.
  * See the COPYING-README file.
  */
-
 class Test_Util extends \Test\TestCase {
 	public function testGetVersion() {
 		$version = \OC_Util::getVersion();
@@ -105,7 +105,7 @@ class Test_Util extends \Test\TestCase {
 		$this->assertEquals('This is a good string without HTML.', $result);
 	}
 
-	function testEncodePath(){
+	function testEncodePath() {
 		$component = '/§#@test%&^ä/-child';
 		$result = OC_Util::encodePath($component);
 		$this->assertEquals("/%C2%A7%23%40test%25%26%5E%C3%A4/-child", $result);
@@ -210,14 +210,12 @@ class Test_Util extends \Test\TestCase {
 	/**
 	 * @dataProvider baseNameProvider
 	 */
-	public function testBaseName($expected, $file)
-	{
+	public function testBaseName($expected, $file) {
 		$base = \OC_Util::basename($file);
 		$this->assertEquals($expected, $base);
 	}
 
-	public function baseNameProvider()
-	{
+	public function baseNameProvider() {
 		return array(
 			array('public_html', '/home/user/public_html/'),
 			array('public_html', '/home/user/public_html'),
@@ -288,11 +286,11 @@ class Test_Util extends \Test\TestCase {
 
 		\OC_User::createUser($uid, "passwd");
 
-		foreach($groups as $group) {
+		foreach ($groups as $group) {
 			\OC_Group::createGroup($group);
 		}
 
-		foreach($membership as $group) {
+		foreach ($membership as $group) {
 			\OC_Group::addToGroup($uid, $group);
 		}
 
@@ -308,7 +306,7 @@ class Test_Util extends \Test\TestCase {
 		\OC_User::deleteUser($uid);
 		\OC_User::setUserId('');
 
-		foreach($groups as $group) {
+		foreach ($groups as $group) {
 			\OC_Group::deleteGroup($group);
 		}
 
@@ -317,7 +315,7 @@ class Test_Util extends \Test\TestCase {
 
 	}
 
-	public function dataProviderForTestIsSharingDisabledForUser()    {
+	public function dataProviderForTestIsSharingDisabledForUser() {
 		return array(
 			// existing groups, groups the user belong to, groups excluded from sharing, expected result
 			array(array('g1', 'g2', 'g3'), array(), array('g1'), false),
@@ -327,8 +325,8 @@ class Test_Util extends \Test\TestCase {
 			array(array('g1', 'g2', 'g3'), array('g1', 'g2'), array('g1'), false),
 			array(array('g1', 'g2', 'g3'), array('g1', 'g2'), array('g1', 'g2'), true),
 			array(array('g1', 'g2', 'g3'), array('g1', 'g2'), array('g1', 'g2', 'g3'), true),
-        );
-    }
+		);
+	}
 
 	/**
 	 * Test default apps
@@ -341,15 +339,21 @@ class Test_Util extends \Test\TestCase {
 		$oldWebRoot = \OC::$WEBROOT;
 		\OC::$WEBROOT = '';
 
-		Dummy_OC_App::setEnabledApps($enabledApps);
+		$appManager = $this->getMock('\OCP\App\IAppManager');
+		$appManager->expects($this->any())
+			->method('isEnabledForUser')
+			->will($this->returnCallback(function($appId) use ($enabledApps){
+				return in_array($appId, $enabledApps);
+		}));
+		Dummy_OC_Util::$appManager = $appManager;
+
 		// need to set a user id to make sure enabled apps are read from cache
 		\OC_User::setUserId($this->getUniqueID());
 		\OCP\Config::setSystemValue('defaultapp', $defaultAppConfig);
-		$this->assertEquals('http://localhost/' . $expectedPath, \OC_Util::getDefaultPageUrl());
+		$this->assertEquals('http://localhost/' . $expectedPath, Dummy_OC_Util::getDefaultPageUrl());
 
 		// restore old state
 		\OC::$WEBROOT = $oldWebRoot;
-		Dummy_OC_App::restore();
 		\OCP\Config::setSystemValue('defaultapp', $oldDefaultApps);
 		\OC_User::setUserId(null);
 	}
@@ -405,18 +409,15 @@ class Test_Util extends \Test\TestCase {
 }
 
 /**
- * Dummy OC Apps class to make it possible to override
- * enabled apps
+ * Dummy OC Util class to make it possible to override the app manager
  */
-class Dummy_OC_App extends OC_App {
-	private static $enabledAppsCacheBackup;
+class Dummy_OC_Util extends OC_Util {
+	/**
+	 * @var \OCP\App\IAppManager
+	 */
+	public static $appManager;
 
-	public static function setEnabledApps($enabledApps) {
-		self::$enabledAppsCacheBackup = self::$enabledAppsCache;
-		self::$enabledAppsCache = $enabledApps;
-	}
-
-	public static function restore() {
-		self::$enabledAppsCache = self::$enabledAppsCacheBackup;
+	protected static function getAppManager() {
+		return self::$appManager;
 	}
 }