[DNSB]

Just got a forced update to K4PC 1.30 however the book I downloaded removed the DRM when imported to calibre. When I attempted to use KF8 => Epub, I got the following error:

Spoiler:

calibre, version 5.3.0
ERROR: Unhandled exception: <b>TypeError</b>:a bytes-like object is required, not 'str'

calibre 5.3 [64bit]  embedded-python: True is64bit: True
Windows-10-10.0.19041-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.19041')
Python 3.8.5
Windows: ('10', '10.0.19041', 'SP0', 'Multiprocessor Free')
Interface language: None
Successfully initialized third party plugins: DeDRM (7, 0, 0) && Annotations (1, 13, 0) && Baen (1, 2, 0) && Barnes & Noble (1, 2, 16) && Calibre Power Search Plugin (1, 6, 0) && Count Pages (1, 10, 0) && Diaps Editing Toolbag (0, 3, 7) && EpubCheck (0, 2, 3) && EpubMerge (2, 11, 0) && EpubSplit (2, 9, 0) && FanFicFare (3, 24, 0) && Fantastic Fiction (1, 4, 0) && Find Duplicates (1, 8, 3) && Goodreads (1, 5, 1) && Hyphenate This! (0, 1, 3) && Job Spy (1, 0, 187) && Kindle hi-res covers (0, 5, 0) && KindleUnpack - The Plugin (0, 82, 3) && Kobo Books (1, 8, 0) && Kobo Utilities (2, 11, 8) && KoboTouchExtended (3, 4, 1) && Modify ePub (1, 6, 1) && Obok DeDRM (6, 7, 0) && Open With (1, 5, 12) && Quality Check (1, 10, 1) && Resize Cover (1, 1, 0) && ScrambleEbook (0, 4, 5) && SmartEject (2, 3, 0) && Smashwords Metadata (1, 0, 2)
Traceback (most recent call last):
  File "calibre_plugins.kindleunpack_plugin.action", line 283, in extract_element
  File "calibre_plugins.kindleunpack_plugin.mobi_stuff", line 127, in unpackEPUB
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 925, in unpackBook
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 842, in process_all_mobi_headers
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 559, in processMobi8
AttributeError: 'NoneType' object has no attribute 'find'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "calibre_plugins.kindleunpack_plugin.action", line 287, in extract_element
  File "calibre_plugins.kindleunpack_plugin.utilities", line 102, in showErrorDlg
  File "traceback.py", line 163, in print_exc
  File "traceback.py", line 105, in print_exception
TypeError: a bytes-like object is required, not 'str'

The results from trying this in Calibre 4.23 portable was similar:

Spoiler:

calibre, version 4.23.0
ERROR: KindleUnpack - The Plugin v0.82.3: 'NoneType' object has no attribute 'find'

Traceback (most recent call last):
  File "calibre_plugins.kindleunpack_plugin.action", line 283, in extract_element
  File "calibre_plugins.kindleunpack_plugin.mobi_stuff", line 127, in unpackEPUB
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 925, in unpackBook
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 842, in process_all_mobi_headers
  File "calibre_plugins.kindleunpack_plugin.kindleunpackcore.kindleunpack", line 559, in processMobi8
AttributeError: 'NoneType' object has no attribute 'find'

Uninstalling 1.30 and reverting back to 1.29 made no difference in either version of calibre. For what it's worth, attemping to unpack the KF8 also abended in line 559.

One item that I forgot to add is this book is a sample.