[KingZorc]

I followed the manual to create a CBC and Calibre throws errors when trying to preview it and convert it to something else.

calibre, version 5.4.2
ERROR: Loading book failed: Failed to open the book at C:\Users\Administrator\Calibre Library\Unknown\Unknown.cbc. Click "Show details" for more info.

Failed to convert book: C:\Users\Administrator\Calibre Library\Unknown\Unknown.cbc with error:
InputFormatPlugin: Comic Input running
on C:\Users\Administrator\Calibre Library\Unknown\Unknown.cbc
Failed to run pipe worker with command: from calibre.srv.render_book import viewer_main; viewer_main()
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 195, in main
  File "<string>", line 1, in <module>
  File "calibre\srv\render_book.py", line 865, in viewer_main
  File "calibre\srv\render_book.py", line 856, in render_for_viewer
  File "calibre\srv\render_book.py", line 833, in render
  File "calibre\ebooks\oeb\iterator\book.py", line 63, in extract_book
  File "calibre\customize\conversion.py", line 245, in __call__
  File "calibre\ebooks\conversion\plugins\comic_input.py", line 174, in convert
  File "calibre\ebooks\conversion\plugins\comic_input.py", line 102, in get_comics_from_collection
ValueError: C:\Users\Administrator\Calibre Library\Unknown\Unknown.cbc is not a valid comic collection no comics.txt was found in the file