Had the wrong Doc input plugin at first, and copied the needed files into the path they were expected in.
But with both the original plugin and the updated one it still fails to find some specific files: 81wh0a.doc & 81wh0a.doc.docx for the original and qkwsmo.doc & qkwsmo.doc.docx in the AppData\Local\Temp\ (etc) folders.
Just from the names, I suspect the plugin is supposed to be creating these, not looking for pre-existing files.
I can't follow the entire error dump so I don't know if it is creating them somewhere else but looking for them here.
Here is the dump:
Spoiler:
calibre, version 2.83.0 (win32, embedded-python: True)
Conversion Error: Failed: Convert book 1 of 1 (AgnesOld)
Convert book 1 of 1 (AgnesOld)
Conversion options changed from defaults:
read_metadata_from_opf: u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\wnaobz.opf'
insert_metadata: True
verbose: 2
epub_flatten: True
output_profile: 'kobo'
Resolved conversion options
calibre version: 2.83.0
{'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': u'original',
'chapter': u"//*[((name()='h1' or name()='h2') and re:test(., '\\s*((chapter|book|section|part)\\s+)|((prolog|pr ologue|epilogue)(\\s+|$))', 'i')) or @class = 'chapter']",
'chapter_mark': u'pagebreak',
'comments': None,
'cover': None,
'debug_pipeline': None,
'dehyphenate': True,
'delete_blank_paragraphs': True,
'disable_font_rescaling': False,
'docx_no_cover': 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': True,
'epub_inline_toc': False,
'epub_toc_at_end': False,
'expand_css': False,
'extra_css': None,
'extract_to': None,
'filter_css': u'',
'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 0x046E1550>,
'insert_blank_line': False,
'insert_blank_line_size': 0.5,
'insert_metadata': True,
'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.KoboReaderOutput object at 0x046E1970>,
'page_breaks_before': u'/',
'prefer_metadata_cover': False,
'preserve_cover_aspect_ratio': False,
'pretty_print': True,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\wnaobz.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': u'',
'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': '[]',
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'verbose': 2,
'wordconv_exe_path': u'c:\\Program Files\\Microsoft Office\\Office12\\Wordconv.exe'}
InputFormatPlugin: DOC Input running
on C:\Users\Michael\AppData\Local\Temp\calibre_oyvxgj \ayxlqu.doc
Convert doc C:\Users\Michael\AppData\Local\Temp\calibre_oyvxgj \ayxlqu.doc to docx via c:\Program Files\Microsoft Office\Office12\Wordconv.exe
Temp directory C:\Users\Michael\AppData\Local\Temp\calibre_oyvxgj \gkrrvddoc_input temp output fileC:\Users\Michael\AppData\Local\Temp\calibre_oy vxgj\gkrrvddoc_input\ayxlqu.doc.docx
Python function terminated unexpectedly
Command '[u'c:\\Program Files\\Microsoft Office\\Office12\\Wordconv.exe', '-oice', '-nme', u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\ayxlqu.doc', u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\gkrrvddoc_input\\ayxlqu.doc.docx']' returned non-zero exit status -3 (Error Code: 1)
Traceback (most recent call last):
File "site.py", line 132, in main
File "site.py", line 109, in run_entry_point
File "site-packages\calibre\utils\ipc\worker.py", line 195, in main
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 33, in gui_convert_override
File "site-packages\calibre\gui2\convert\gui_conversion.py", line 26, in gui_convert
File "site-packages\calibre\ebooks\conversion\plumber.py", line 1088, in run
File "site-packages\calibre\customize\conversion.py", line 245, in __call__
File "calibre_plugins.doc_input.__init__", line 53, in convert
File "subprocess.py", line 540, in check_call
subprocess.CalledProcessError: Command '[u'c:\\Program Files\\Microsoft Office\\Office12\\Wordconv.exe', '-oice', '-nme', u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\ayxlqu.doc', u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\gkrrvddoc_input\\ayxlqu.doc.docx']' returned non-zero exit status -3
OK. That's odd. Essentially the same error, but different .doc & .doc.docx files missing -- and different gkrrvddoc_input directory -- ???
read_metadata_from_opf: u'C:\\Users\\Michael\\AppData\\Local\\Temp\\calibr e_oyvxgj\\wnaobz.opf'
Whole lotta files created in that calibre_oyvxgj directory, but no .opf or .doc files, no gkrrvddoc_input directory (& thus no .doc.docx file either.)