[crphoto]

Originally Posted by kovidgoyal

Just click save, quit and re-open your book, you will be fine. Or use save a copy if you want to be doubly safe. And if you can figure out what you did to cause that error, it would help me fix it.

I have the same error, here is my detailed list error as it gives me.

Spoiler:

calibre, version 7.23.0 (win32, embedded-python: True)
Conversion error: Failed: Convert book 1 of 1 (In Awe of Thy Word)

Convert book 1 of 1 (In Awe of Thy Word)
Conversion options changed from defaults:
output_profile: 'kindle_pw3'
pdf_header_regex: None
verbose: 2
pdf_footer_regex: None
cover: 'C:\\Users\\croll\\AppData\\Local\\Temp\\calibre_e u90lxye\\lwwz8s8f.jpeg'
read_metadata_from_opf: 'C:\\Users\\croll\\AppData\\Local\\Temp\\calibre_e u90lxye\\68gpxikg.opf'
Resolved conversion options
calibre version: 7.23.0
{'add_alt_text_to_img': False,
'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': 'original',