diff --git a/apps/theming/lib/ThemingDefaults.php b/apps/theming/lib/ThemingDefaults.php
index 0a9d5a6cc1..5dd22fb632 100644
--- a/apps/theming/lib/ThemingDefaults.php
+++ b/apps/theming/lib/ThemingDefaults.php
@@ -23,6 +23,8 @@
 namespace OCA\Theming;
 
 
+use OCP\App\AppPathNotFoundException;
+use OCP\App\IAppManager;
 use OCP\Files\IAppData;
 use OCP\ICacheFactory;
 use OCP\IConfig;
@@ -41,6 +43,10 @@ class ThemingDefaults extends \OC_Defaults {
 	private $appData;
 	/** @var ICacheFactory */
 	private $cacheFactory;
+	/** @var Util */
+	private $util;
+	/** @var IAppManager */
+	private $appManager;
 	/** @var string */
 	private $name;
 	/** @var string */
@@ -49,8 +55,7 @@ class ThemingDefaults extends \OC_Defaults {
 	private $slogan;
 	/** @var string */
 	private $color;
-	/** @var Util */
-	private $util;
+
 	/** @var string */
 	private $iTunesAppId;
 	/** @var string */
@@ -68,13 +73,15 @@ class ThemingDefaults extends \OC_Defaults {
 	 * @param IAppData $appData
 	 * @param ICacheFactory $cacheFactory
 	 * @param Util $util
+	 * @param IAppManager $appManager
 	 */
 	public function __construct(IConfig $config,
 								IL10N $l,
 								IURLGenerator $urlGenerator,
 								IAppData $appData,
 								ICacheFactory $cacheFactory,
-								Util $util
+								Util $util,
+								IAppManager $appManager
 	) {
 		parent::__construct();
 		$this->config = $config;
@@ -83,6 +90,7 @@ class ThemingDefaults extends \OC_Defaults {
 		$this->appData = $appData;
 		$this->cacheFactory = $cacheFactory;
 		$this->util = $util;
+		$this->appManager = $appManager;
 
 		$this->name = parent::getName();
 		$this->url = parent::getBaseUrl();
@@ -269,10 +277,12 @@ class ThemingDefaults extends \OC_Defaults {
 			return $this->urlGenerator->linkToRoute('theming.Icon.getTouchIcon', ['app' => $app]) . '?v=' . $cacheBusterValue;
 		}
 		if ($image === 'manifest.json') {
-			$appPath = \OC_App::getAppPath($app);
-			if ($appPath && file_exists($appPath . '/img/manifest.json')) {
-				return false;
-			}
+			try {
+				$appPath = $this->appManager->getAppPath($app);
+				if (file_exists($appPath . '/img/manifest.json')) {
+					return false;
+				}
+			} catch (AppPathNotFoundException $e) {}
 			return $this->urlGenerator->linkToRoute('theming.Theming.getManifest') . '?v=' . $cacheBusterValue;
 		}
 		return false;
diff --git a/apps/theming/tests/ThemingDefaultsTest.php b/apps/theming/tests/ThemingDefaultsTest.php
index 48099e8be0..b1d86bff43 100644
--- a/apps/theming/tests/ThemingDefaultsTest.php
+++ b/apps/theming/tests/ThemingDefaultsTest.php
@@ -24,6 +24,7 @@
 namespace OCA\Theming\Tests;
 
 use OCA\Theming\ThemingDefaults;
+use OCP\App\IAppManager;
 use OCP\Files\IAppData;
 use OCA\Theming\Util;
 use OCP\Files\NotFoundException;
@@ -55,6 +56,8 @@ class ThemingDefaultsTest extends TestCase {
 	private $util;
 	/** @var ICache|\PHPUnit_Framework_MockObject_MockObject */
 	private $cache;
+	/** @var IAppManager|\PHPUnit_Framework_MockObject_MockObject */
+	private $appManager;
 
 	public function setUp() {
 		parent::setUp();
@@ -65,6 +68,7 @@ class ThemingDefaultsTest extends TestCase {
 		$this->cacheFactory = $this->createMock(ICacheFactory::class);
 		$this->cache = $this->createMock(ICache::class);
 		$this->util = $this->createMock(Util::class);
+		$this->appManager = $this->createMock(IAppManager::class);
 		$this->defaults = new \OC_Defaults();
 		$this->cacheFactory
 			->expects($this->any())
@@ -77,7 +81,8 @@ class ThemingDefaultsTest extends TestCase {
 			$this->urlGenerator,
 			$this->appData,
 			$this->cacheFactory,
-			$this->util
+			$this->util,
+			$this->appManager
 		);
 	}
 
diff --git a/lib/private/Server.php b/lib/private/Server.php
index fb0aa76cd1..a20d9ccfc0 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -892,7 +892,8 @@ class Server extends ServerContainer implements IServerContainer {
 					$c->getURLGenerator(),
 					$c->getAppDataDir('theming'),
 					$c->getMemCacheFactory(),
-					new Util($c->getConfig(), $this->getAppManager(), $this->getAppDataDir('theming'))
+					new Util($c->getConfig(), $this->getAppManager(), $this->getAppDataDir('theming')),
+					$this->getAppManager()
 				);
 			}
 			return new \OC_Defaults();