diff --git a/lib/private/Preview/Watcher.php b/lib/private/Preview/Watcher.php
index 7f4593f9fe3..ad6fed56020 100644
--- a/lib/private/Preview/Watcher.php
+++ b/lib/private/Preview/Watcher.php
@@ -61,6 +61,9 @@ class Watcher {
 		}
 
 		try {
+			if (is_null($node->getId())) {
+				return;
+			}
 			$folder = $this->appData->getFolder((string)$node->getId());
 			$folder->delete();
 		} catch (NotFoundException $e) {