 
I am having the worst luck trying to catalog my library; it worked long (eons) ago, but these days I keep getting the following error:
Generate catalog
DeACSM v0.0.12: Copying needed library files from plugin zip
Integration status: True
Initialized urlfixer
 Sections: Authors, Titles, Series, Genres, Recently Added, Descriptions
Catalog_EPUB_MOBI('Calibre Library'): Generating azw3 for kobo in GUI environment, locale: 'English'
 connected_device: 'None'
 book count: 12555
 opts:
  author_clip: 100
  catalog_title: 'My Books AZW'
  connected_kindle: False
  creator: 'Tuesday, December 7, 2021'
  cross_reference_authors: True
  description_clip: 380
  exclude_genre: '\\[.+\\]|^\\+$'
  exclusion_rules: (('Catalogs', 'Tags', 'Catalog'),)
  fmt: 'azw3'
  genre_source_field: 'Tags'
  header_note_source_field: ''
  merge_comments_rule: '::True'
  output_profile: 'kobo'
  prefix_rules: ()
  search_text: None
  sort_by: None
  sort_descriptions_by_author: True
  sync: False
  thumb_width: '1.00'
  use_existing_cover: False
 Begin catalog source generation (0:00:00) 
unhandled exception in catalog generator
Traceback (most recent call last):
  File "runpy.py", line 194, in _run_module_as_main
  File "runpy.py", line 87, in _run_code
  File "site.py", line 82, in <module>
  File "site.py", line 77, in main
  File "site.py", line 49, in run_entry_point
  File "calibre\utils\ipc\worker.py", line 216, in main
  File "calibre\gui2\convert\gui_conversion.py", line 81, in gui_catalog
  File "calibre\library\catalogs\epub_mobi.py", line 406, in run
  File "calibre\library\catalogs\epub_mobi_builder.py  ", line 330, in build_sources
  File "calibre\library\catalogs\epub_mobi_builder.py  ", line 2189, in generate_html_by_genres
  File "calibre\library\catalogs\epub_mobi_builder.py  ", line 2296, in generate_html_by_genre
  File "calibre\library\catalogs\epub_mobi_builder.py  ", line 1382, in format_prefix
  File "calibre\ebooks\BeautifulSoup.py", line 34, in BeautifulSoup
  File "calibre\ebooks\BeautifulSoup.py", line 23, in parse_html
  File "html5_parser\soup.py", line 130, in parse
ModuleNotFoundError: No module named 'html5_parser.book_3264'
The book number will change between runs (I presume this is the number that is attached to the book in the library files, correct?); I am running the latest version of Calibre on Windows 10, with 16 Gigs of RAM available, and approximately 12.5K books to catalog.  Does anyone recognize this problem, and have a solution?  Thanks in advance.