[rlh3]

ducks:

Both options give me an "Unknown string format: National Geographic [1889-04]"

The date format of the published (pubdate) field is already set to the correct format (mmm yyyy)

rlh3

calibre, version 7.19.0
ERROR: Failed: Unknown string format: National Geographic [1889-04]

Traceback (most recent call last):
  File "calibre\gui2\dialogs\metadata_bulk.py", line 198, in do_it
  File "calibre\gui2\dialogs\metadata_bulk.py", line 535, in do_all
  File "calibre\db\cache.py", line 85, in call_func_with_lock
  File "calibre\db\cache.py", line 1636, in set_field
  File "calibre\db\write.py", line 568, in set_books
  File "calibre\db\write.py", line 568, in <dictcomp>
  File "calibre\db\write.py", line 81, in adapt_date
  File "calibre\utils\date.py", line 138, in parse_only_date
  File "calibre\utils\date.py", line 114, in parse_date
  File "dateutil\parser\_parser.py", line 1368, in parse
  File "dateutil\parser\_parser.py", line 643, in parse
dateutil.parser._parser.ParserError: Unknown string format: National Geographic [1889-04]