diff --git a/src/Services/DatabaseBackup/AbstractDatabaseBackup.php b/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
index 1660e720..c46b6e71 100644
--- a/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
+++ b/src/Services/DatabaseBackup/AbstractDatabaseBackup.php
@@ -67,7 +67,7 @@ public function init(array $metadatas, array $classNames, bool $append = false):
      */
     protected function isBackupUpToDate(string $backup): bool
     {
-        $backupLastModifiedDateTime = DateTime::createFromFormat('U', filemtime($backup));
+        $backupLastModifiedDateTime = DateTime::createFromFormat('U', (string) filemtime($backup));
 
         $loader = $this->fixturesLoaderFactory->getFixtureLoader($this->classNames);