diff --git a/app/smb_processor.py b/app/smb_processor.py
index 323603a..9352d2a 100644
--- a/app/smb_processor.py
+++ b/app/smb_processor.py
@@ -66,8 +66,14 @@ def _list_pdf_files(source_path: str) -> list[str]:
 
 
 def _read_smb_file(filepath: str) -> bytes:
-    """Read a file from SMB share into memory."""
-    with smbclient.open_file(filepath, mode="rb") as f:
+    """Read a file from SMB share into memory.
+
+    share_access="rwd" allows concurrent read/write/delete operations on the same
+    file, which is required because smbclient keeps the underlying SMB connection
+    in a pool. Without this, subsequent rename/delete on the file fails with
+    STATUS_ACCESS_DENIED until the session is closed.
+    """
+    with smbclient.open_file(filepath, mode="rb", share_access="rwd") as f:
         return f.read()