An epub book I created with ConTeXt displays fine in version 3 on W10/64. With version 4 (tested with 4.4, 4.5, 4.8) it fails with:\
Spoiler:
calibre, version 4.8.0
ERROR: Loading book failed: Failed to open the book at C:\Users\micro\Documents\Calibre Library\context mkiv\An Illustrated Taxonomy of Misquotat (90)\An Illustrated Taxonomy of Misq - context mkiv.epub. Click "Show details" for more info.
Traceback (most recent call last):
File "site-packages\calibre\gui2\viewer\ui.py", line 371, in _load_ebook_worker
File "site-packages\calibre\gui2\viewer\convert_book.py", line 234, in prepare_book
File "site-packages\calibre\gui2\viewer\convert_book.py", line 191, in do_convert
ConversionFailure: Failed to convert book: C:\Users\micro\Documents\Calibre Library\context mkiv\An Illustrated Taxonomy of Misquotat (90)\An Illustrated Taxonomy of Misq - context mkiv.epub with error:
InputFormatPlugin: EPUB Input running
on C:\Users\micro\Documents\Calibre Library\context mkiv\An Illustrated Taxonomy of Misquotat (90)\An Illustrated Taxonomy of Misq - context mkiv.epub
Failed to run pipe worker with command: from calibre.srv.render_book import viewer_main; viewer_main()
Python function terminated unexpectedly
Invalid input object: str (Error Code: 1)
Traceback (most recent call last):
File "site.py", line 114, in main
File "site.py", line 88, in run_entry_point
File "site-packages\calibre\utils\ipc\worker.py", line 189, in main
File "<string>", line 1, in <module>
File "site-packages\calibre\srv\render_book.py", line 848, in viewer_main
File "site-packages\calibre\srv\render_book.py", line 841, in render_for_viewer
File "site-packages\calibre\srv\render_book.py", line 820, in render
File "site-packages\calibre\srv\render_book.py", line 621, in process_exploded_book
File "site-packages\calibre\srv\render_book.py", line 305, in create_cover_page
File "site-packages\calibre\srv\render_book.py", line 258, in find_epub_cover
File "site-packages\calibre\ebooks\oeb\polish\cover.py", line 287, in find_cover_image_in_page
File "src/lxml/xpath.pxi", line 432, in lxml.etree.XPath.__call__
File "src/lxml/apihelpers.pxi", line 41, in lxml.etree._documentOrRaise
TypeError: Invalid input object: str
Debug log output:
calibre Debug log
calibre 4.8 [64bit] embedded-python: True is64bit: True
Windows-10-10.0.18362-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.18362')
Python 2.7.16+
Windows: ('10', '10.0.18362', 'SP0', u'Multiprocessor Free')
Interface language: None
calibre 4.8 [64bit] embedded-python: True is64bit: True
Windows-10-10.0.18362-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '10', '10.0.18362')
Python 2.7.16+
Windows: ('10', '10.0.18362', 'SP0', u'Multiprocessor Free')
Interface language: None
Turning on automatic hidpi scaling
devicePixelRatio: 2.0
logicalDpi: 96.0 x 96.0
physicalDpi: 141.356521739 x 141.402061856
Using calibre Qt style: True
[0.00] Starting up...
[0.00] Showing splash screen...
[0.50] splash screen shown
[0.50] Initializing db...
[0.50] db initialized
[0.50] Constructing main UI...
[1.88] main UI initialized...
[1.88] Hiding splash screen
[12.17] splash screen hidden
[12.17] Started up in 12.17 seconds with 9 books
Worker Launch took: 0.0989999771118
Advice?