diff --git a/lib/private/Files/Cache/Cache.php b/lib/private/Files/Cache/Cache.php
index a4290549dd92c..01586521a043f 100644
--- a/lib/private/Files/Cache/Cache.php
+++ b/lib/private/Files/Cache/Cache.php
@@ -870,7 +870,7 @@ public function correctFolderSize($path, $data = null, $isBackgroundScan = false
 			}
 			if ($isBackgroundScan) {
 				$parentData = $this->get($parent);
-				if ($parentData['size'] !== -1 && $this->getIncompleteChildrenCount($parentData['fileid']) === 0) {
+				if ($parentData !== false && $parentData['size'] !== -1 && $this->getIncompleteChildrenCount($parentData['fileid']) === 0) {
 					$this->correctFolderSize($parent, $parentData, $isBackgroundScan);
 				}
 			} else {