diff --git a/src/PhpImap/Mailbox.php b/src/PhpImap/Mailbox.php
index 8e1803b9..aafaa4fc 100644
--- a/src/PhpImap/Mailbox.php
+++ b/src/PhpImap/Mailbox.php
@@ -1348,6 +1348,7 @@ public function downloadAttachment(DataPartInfo $dataInfo, array $params, object
             $fileName = $this->decodeMimeStr($fileName);
             $fileName = $this->decodeRFC2231($fileName);
         }
+        $fileName = str_replace('/', ' ', $fileName);
 
         /** @var scalar|array|object|null */
         $sizeInBytes = $partStructure->bytes ?? null;