diff --git a/apps/files_sharing/lib/Cache.php b/apps/files_sharing/lib/Cache.php
index d9cf5d80b8..1c311935bb 100644
--- a/apps/files_sharing/lib/Cache.php
+++ b/apps/files_sharing/lib/Cache.php
@@ -27,6 +27,7 @@
 
 namespace OCA\Files_Sharing;
 
+use OC\Files\Cache\FailedCache;
 use OC\Files\Cache\Wrapper\CacheJail;
 use OCP\Files\Cache\ICacheEntry;
 
@@ -68,7 +69,13 @@ class Cache extends CacheJail {
 
 	public function getCache() {
 		if (is_null($this->cache)) {
-			$this->cache = $this->storage->getSourceStorage()->getCache();
+			$sourceStorage = $this->storage->getSourceStorage();
+			if ($sourceStorage) {
+				$this->cache = $sourceStorage->getCache();
+			} else {
+				// don't set $this->cache here since sourceStorage will be set later
+				return new FailedCache();
+			}
 		}
 		return $this->cache;
 	}