diff --git a/lib/private/Files/View.php b/lib/private/Files/View.php
index 2516b782ee..8322576c5c 100644
--- a/lib/private/Files/View.php
+++ b/lib/private/Files/View.php
@@ -1933,7 +1933,7 @@ class View {
 		if ($mount) {
 			try {
 				$storage = $mount->getStorage();
-				if ($storage->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
+				if ($storage && $storage->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
 					$storage->acquireLock(
 						$mount->getInternalPath($absolutePath),
 						$type,
@@ -1974,7 +1974,7 @@ class View {
 		if ($mount) {
 			try {
 				$storage = $mount->getStorage();
-				if ($storage->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
+				if ($storage && $storage->instanceOfStorage('\OCP\Files\Storage\ILockingStorage')) {
 					$storage->changeLock(
 						$mount->getInternalPath($absolutePath),
 						$type,
diff --git a/lib/private/Share20/Manager.php b/lib/private/Share20/Manager.php
index e71b6f9832..df9a06e3a9 100644
--- a/lib/private/Share20/Manager.php
+++ b/lib/private/Share20/Manager.php
@@ -1430,6 +1430,9 @@ class Manager implements IManager {
 		if ($path->getId() !== $userFolder->getId() && !$userFolder->isSubNode($path)) {
 			$nodes = $userFolder->getById($path->getId());
 			$path = array_shift($nodes);
+			if ($path->getOwner() === null) {
+				return [];
+			}
 			$owner = $path->getOwner()->getUID();
 		}