diff --git a/backup_imap/backup_imap.py b/backup_imap/backup_imap.py
index c438563..529f745 100644
--- a/backup_imap/backup_imap.py
+++ b/backup_imap/backup_imap.py
@@ -65,9 +65,10 @@ class BackupImap:
         list_response, list_data = self.imap.list(f"\"{mailbox}\"", '*')
         if list_response == 'OK':
             for subdir in list_data:
-                sub_mailbox = self._parse_mailbox(subdir)
-                if sub_mailbox != mailbox:
-                    self._process_mailbox(self._parse_mailbox(subdir))
+                if subdir:
+                    sub_mailbox = self._parse_mailbox(subdir)
+                    if sub_mailbox != mailbox:
+                        self._process_mailbox(self._parse_mailbox(subdir))
 
         self._log.debug(
             "Seleting mailbox '%s'",