[ComputerGranny]

I am trying to use Calibre to convert a Kobo book to epub. I have been able to do this successfully. However, recently I have been getting error messages saying the conversion failed. The Kobo Obok DeDRM shows the book and I can import it into Calibre successfully. However, I'm getting a failure error on conversion. I am posting the error details. Hopefully, someone smarter than me can figure out why it's failing. Thanks in advance.

Spoiler:

calibre, version 8.11.1 (win32, embedded-python: True)
Conversion error: Failed: Convert book 1 of 1 (The Golden Chance)

Convert book 1 of 1 (The Golden Chance)
DeDRM v10.0.9: Trying to decrypt 2mb233m5.epub
DeDRM v10.0.9: Verifying zip archive integrity
DeDRM v10.0.9: Post-processing took 0.0 seconds
DeDRM v10.0.9: Finished after 0.3 seconds
Conversion options changed from defaults:
output_profile: 'generic_eink'
verbose: 2
read_metadata_from_opf: 'C:\\Users\\shand\\AppData\\Local\\Temp\\calibre-j6uwwcfh\\mcyktgij.opf'
Resolved conversion options
calibre version: 8.11.1
{'add_alt_text_to_img': False,
'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': 'original',
'chapter': "//*[((name()='h1' or name()='h2') and re:test(., "
"'\\s*((chapter|book|section|part)\\s+)|((prolog|p rologue|epilogue)(\\s+|$))', "
"'i')) or @class = 'chapter']",
'chapter_mark': 'pagebreak',
'comments': None,
'cover': None,
'debug_pipeline': None,
'dehyphenate': True,
'delete_blank_paragraphs': True,
'disable_font_rescaling': False,
'dont_split_on_page_breaks': False,
'duplicate_links_in_toc': False,
'embed_all_fonts': False,
'embed_font_family': None,
'enable_heuristics': False,
'epub_flatten': False,
'epub_inline_toc': False,
'epub_max_image_size': 'none',
'epub_toc_at_end': False,
'epub_version': '2',
'expand_css': False,
'extra_css': None,
'extract_to': None,
'filter_css': '',
'fix_indents': True,
'flow_size': 260,
'font_size_mapping': None,
'format_scene_breaks': True,
'html_unwrap_factor': 0.4,
'input_encoding': None,
'input_profile': <calibre.customize.profiles.InputProfile object at 0x000002B831D05390>,
'insert_blank_line': False,
'insert_blank_line_size': 0.5,
'insert_metadata': False,
'isbn': None,
'italicize_common_cases': True,
'keep_ligatures': False,
'language': None,
'level1_toc': None,
'level2_toc': None,
'level3_toc': None,
'line_height': 0.0,
'linearize_tables': False,
'margin_bottom': 5.0,
'margin_left': 5.0,
'margin_right': 5.0,
'margin_top': 5.0,
'markup_chapter_headings': True,
'max_toc_links': 50,
'minimum_line_height': 120.0,
'no_chapters_in_toc': False,
'no_default_epub_cover': False,
'no_inline_navbars': False,
'no_svg_cover': False,
'output_profile': <calibre.customize.profiles.GenericEink object at 0x000002B831D14D10>,
'page_breaks_before': '/',
'prefer_metadata_cover': False,
'preserve_cover_aspect_ratio': False,
'pretty_print': True,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': 'C:\\Users\\shand\\AppData\\Local\\Temp\\calibre-j6uwwcfh\\mcyktgij.opf',
'remove_fake_margins': True,
'remove_first_image': False,
'remove_paragraph_spacing': False,
'remove_paragraph_spacing_indent_size': 1.5,
'renumber_headings': True,
'replace_scene_breaks': '',
'search_replace': '[]',
'series': None,
'series_index': None,
'smarten_punctuation': False,
'sr1_replace': None,
'sr1_search': None,
'sr2_replace': None,
'sr2_search': None,
'sr3_replace': None,
'sr3_search': None,
'start_reading_at': None,
'subset_embedded_fonts': False,
'tags': None,
'timestamp': None,
'title': None,
'title_sort': None,
'toc_filter': None,
'toc_threshold': 6,
'toc_title': None,
'transform_css_rules': '[]',
'transform_html_rules': '[]',
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'verbose': 2}
DeDRM v10.0.9: Trying to decrypt j0hbevcz.epub
DeDRM v10.0.9: Verifying zip archive integrity
DeDRM v10.0.9: Post-processing took 0.0 seconds
DeDRM v10.0.9: Finished after 0.2 seconds
InputFormatPlugin: EPUB Input running
on C:\Users\shand\AppData\Local\Temp\calibre-j6uwwcfh\4u1pe0l_.epub
Found HTML cover titlepage.xhtml
Parsing all content...
Parsing index_split_019.html ...
Failed to parse content in index_split_019.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_011.html ...
Failed to parse content in index_split_011.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_013.html ...
Failed to parse content in index_split_013.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_009.html ...
Failed to parse content in index_split_009.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_017.html ...
Failed to parse content in index_split_017.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_015.html ...
Failed to parse content in index_split_015.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_003.html ...
Failed to parse content in index_split_003.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_005.html ...
Failed to parse content in index_split_005.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_007.html ...
Failed to parse content in index_split_007.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_008.html ...
Failed to parse content in index_split_008.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_014.html ...
Failed to parse content in index_split_014.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_020.html ...
Failed to parse content in index_split_020.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_021.html ...
Failed to parse content in index_split_021.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing stylesheet.css ...
Parsing index_split_010.html ...
Failed to parse content in index_split_010.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing titlepage.xhtml ...
Failed to parse content in titlepage.xhtml
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_002.html ...
Failed to parse content in index_split_002.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_001.html ...
Failed to parse content in index_split_001.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_000.html ...
Failed to parse content in index_split_000.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_004.html ...
Failed to parse content in index_split_004.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_006.html ...
Failed to parse content in index_split_006.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_012.html ...
Failed to parse content in index_split_012.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_016.html ...
Failed to parse content in index_split_016.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_018.html ...
Failed to parse content in index_split_018.html
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 197, in _manifest_prune_invalid
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing css/kobo.css ...
Parsing page_styles.css ...
Referenced file 'index_split_019.html' not in manifest
Referenced file 'index_split_017.html' not in manifest
Referenced file 'index_split_004.html' not in manifest
Referenced file 'index_split_009.html' not in manifest
Referenced file 'index_split_002.html' not in manifest
Referenced file 'index_split_021.html' not in manifest
Referenced file 'index_split_011.html' not in manifest
Referenced file 'index_split_018.html' not in manifest
Referenced file 'index_split_020.html' not in manifest
Referenced file 'index_split_003.html' not in manifest
Referenced file 'index_split_016.html' not in manifest
Referenced file 'index_split_005.html' not in manifest
Referenced file 'index_split_015.html' not in manifest
Referenced file 'index_split_012.html' not in manifest
Referenced file 'index_split_010.html' not in manifest
Referenced file 'index_split_014.html' not in manifest
Referenced file 'index_split_013.html' not in manifest
Referenced file 'index_split_007.html' not in manifest
Referenced file 'index_split_001.html' not in manifest
Referenced file 'index_split_006.html' not in manifest
Referenced file 'index_split_008.html' not in manifest
Referenced file 'index_split_000.html' not in manifest
Parsing index_split_014.html ...
Failed to read from manifest entry with id: added15, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_019.html ...
Failed to read from manifest entry with id: added, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_017.html ...
Failed to read from manifest entry with id: added1, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_018.html ...
Failed to read from manifest entry with id: added7, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_020.html ...
Failed to read from manifest entry with id: added8, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_003.html ...
Failed to read from manifest entry with id: added9, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_010.html ...
Failed to read from manifest entry with id: added14, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_012.html ...
Failed to read from manifest entry with id: added13, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_006.html ...
Failed to read from manifest entry with id: added19, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_008.html ...
Failed to read from manifest entry with id: added20, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_001.html ...
Failed to read from manifest entry with id: added18, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_005.html ...
Failed to read from manifest entry with id: added11, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_016.html ...
Failed to read from manifest entry with id: added10, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_007.html ...
Failed to read from manifest entry with id: added17, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_013.html ...
Failed to read from manifest entry with id: added16, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_004.html ...
Failed to read from manifest entry with id: added2, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_002.html ...
Failed to read from manifest entry with id: added4, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_009.html ...
Failed to read from manifest entry with id: added3, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_021.html ...
Failed to read from manifest entry with id: added5, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_011.html ...
Failed to read from manifest entry with id: added6, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_000.html ...
Failed to read from manifest entry with id: added21, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Parsing index_split_015.html ...
Failed to read from manifest entry with id: added12, ignoring
Traceback (most recent call last):
File "calibre\ebooks\oeb\reader.py", line 219, in _manifest_add_missing
File "calibre\ebooks\oeb\base.py", line 1058, in data
File "calibre\ebooks\oeb\base.py", line 968, in _parse_xhtml
File "calibre\ebooks\oeb\parse_utils.py", line 232, in parse_html
AttributeError: 'NoneType' object has no attribute 'tag'

Spine item 'id222' not found
Spine item 'id221' not found
Spine item 'id220' not found
Spine item 'id219' not found
Spine item 'id218' not found
Spine item 'id217' not found
Spine item 'id216' not found
Spine item 'id215' not found
Spine item 'id214' not found
Spine item 'id213' not found
Spine item 'id212' not found
Spine item 'id211' not found
Spine item 'id210' not found
Spine item 'id29' not found
Spine item 'id28' not found
Spine item 'id27' not found
Spine item 'id26' not found
Spine item 'id25' not found
Spine item 'id24' not found
Spine item 'id23' not found
Spine item 'id22' not found
Spine item 'id21' not found
Traceback (most recent call last):
File "runpy.py", line 198, in _run_module_as_main
File "runpy.py", line 88, in _run_code
File "site.py", line 83, in <module>
File "site.py", line 78, in main
File "site.py", line 50, in run_entry_point
File "calibre\utils\ipc\worker.py", line 213, in main
File "calibre\gui2\convert\gui_conversion.py", line 39, in gui_convert_override
File "calibre\gui2\convert\gui_conversion.py", line 26, in gui_convert
File "calibre\ebooks\conversion\plumber.py", line 1099, in run
File "calibre\ebooks\conversion\plumber.py", line 1309, in create_oebbook
File "calibre\ebooks\oeb\reader.py", line 97, in __call__
File "calibre\ebooks\oeb\reader.py", line 724, in _all_from_opf
File "calibre\ebooks\oeb\reader.py", line 369, in _spine_from_opf
calibre.ebooks.oeb.base.OEBError: Spine is empty