diff --git a/apps/dav/lib/Files/FileSearchBackend.php b/apps/dav/lib/Files/FileSearchBackend.php
index 17a4c2b139420..1ea5f914e1093 100644
--- a/apps/dav/lib/Files/FileSearchBackend.php
+++ b/apps/dav/lib/Files/FileSearchBackend.php
@@ -273,7 +273,7 @@ private function castValue($propertyName, $value) {
 							return max(0, 0 + $value);
 						}
 						$date = \DateTime::createFromFormat(\DateTime::ATOM, $value);
-						return ($date instanceof \DateTime) ? $date->getTimestamp() : 0;
+						return ($date instanceof \DateTime && $date->getTimestamp() !== false) ? $date->getTimestamp() : 0;
 					default:
 						return $value;
 				}