diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
index b7dff4be3ac9f..237c604f66180 100644
--- a/apps/dav/lib/CalDAV/CalDavBackend.php
+++ b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -445,7 +445,7 @@ private function getUserDisplayName($uid) {
 
 		return $this->userDisplayNames[$uid];
 	}
-	
+
 	/**
 	 * @return array
 	 */
@@ -1238,7 +1238,9 @@ function deleteCalendarObject($calendarId, $objectUri, $calendarType=self::CALEN
 		$stmt = $this->db->prepare('DELETE FROM `*PREFIX*calendarobjects` WHERE `calendarid` = ? AND `uri` = ? AND `calendartype` = ?');
 		$stmt->execute([$calendarId, $objectUri, $calendarType]);
 
-		$this->purgeProperties($calendarId, $data['id'], $calendarType);
+		if (is_array($data)) {
+			$this->purgeProperties($calendarId, $data['id'], $calendarType);
+		}
 
 		$this->addChange($calendarId, $objectUri, 3, $calendarType);
 	}