diff --git a/scripts/download-gmail-attachments.py b/scripts/download-gmail-attachments.py
index 8aa04c2..01ede0f 100755
--- a/scripts/download-gmail-attachments.py
+++ b/scripts/download-gmail-attachments.py
@@ -62,6 +62,12 @@ def unique_path(path: Path, overwrite: bool) -> Path:
         counter += 1
 
 
+def quote_imap_string(value: str) -> str:
+    """Maskiert einen Text als quotierten IMAP-String."""
+    escaped = value.replace("\\", "\\\\").replace('"', '\\"')
+    return f'"{escaped}"'
+
+
 def message_folder(message: Message, message_id: bytes) -> str:
     date_header = decode_mime_header(message.get("Date"))
     subject = safe_filename(decode_mime_header(message.get("Subject"), "ohne-betreff"), "ohne-betreff")
@@ -132,7 +138,9 @@ def download_attachments(args: argparse.Namespace) -> DownloadStats:
         output_dir = args.output.expanduser().resolve()
         output_dir.mkdir(parents=True, exist_ok=True)
 
-        status, select_data = client.select(args.mailbox, readonly=True)
+        # imaplib quotiert Argumente nicht automatisch. Gmail-Postfächer wie
+        # "[Gmail]/All Mail" würden deshalb wegen des Leerzeichens fehlschlagen.
+        status, select_data = client.select(quote_imap_string(args.mailbox), readonly=True)
         if status != "OK":
             details = b" ".join(select_data or []).decode("utf-8", errors="replace")
             raise RuntimeError(