diff --git a/src/Persistence/Mapping/Driver/FileDriver.php b/src/Persistence/Mapping/Driver/FileDriver.php
index d3e6b0c8..d2ba1663 100644
--- a/src/Persistence/Mapping/Driver/FileDriver.php
+++ b/src/Persistence/Mapping/Driver/FileDriver.php
@@ -173,7 +173,7 @@ abstract protected function loadMappingFile(string $file);
     protected function initialize()
     {
         $this->classCache = [];
-        if ($this->globalBasename === null) {
+        if ($this->globalBasename === '') {
             return;
         }