Conversion Problem Mobi to AZW3

[Klaw]

Message always Failed to convert.
Thanks

Spoiler:

Convert book 1 of 1 (Mass Casualties A Young Medic's True Sto)
Resolved conversion options
calibre version: 1.23.0
{'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,
'dont_compress': False,
'duplicate_links_in_toc': False,
'embed_all_fonts': False,
'embed_font_family': None,
'enable_heuristics': False,
'expand_css': False,
'extra_css': None,
'extract_to': None,
'filter_css': u'',
'fix_indents': True,
'font_size_mapping': None,
'format_scene_breaks': True,
'html_unwrap_factor': 0.4,
'input_encoding': None,
'input_profile': <calibre.customize.profiles.InputProfile object at 0x10769c0d0>,
'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,
'mobi_toc_at_start': False,
'no_chapters_in_toc': False,
'no_inline_navbars': False,
'no_inline_toc': False,
'output_profile': <calibre.customize.profiles.KindlePaperWhiteOutp ut object at 0x10769c810>,
'page_breaks_before': u"//*[name()='h1' or name()='h2']",
'prefer_author_sort': False,
'prefer_metadata_cover': False,
'pretty_print': False,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': u'/var/folders/v4/206j4fd13czf9984lw2d7h0c0000gn/T/calibre_1.23.0_tmp_lJX_gj/XR0gjv.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,
'share_not_sync': False,
'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,
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'verbose': 2}
Python function terminated unexpectedly: unpack requires a string argument of length 2
InputFormatPlugin: MOBI Input running
on /var/folders/v4/206j4fd13czf9984lw2d7h0c0000gn/T/calibre_1.23.0_tmp_lJX_gj/qvFrDT.mobi
Traceback (most recent call last):
File "/Applications/calibre.app/Contents/Resources/Python/lib/python2.7/site.py", line 208, in main
return run_entry_point()
File "/Applications/calibre.app/Contents/Resources/Python/lib/python2.7/site.py", line 114, in run_entry_point
return getattr(pmod, func)()
File "site-packages/calibre/utils/ipc/worker.py", line 192, in main
File "site-packages/calibre/gui2/convert/gui_conversion.py", line 31, in gui_convert_override
File "site-packages/calibre/gui2/convert/gui_conversion.py", line 25, in gui_convert
File "site-packages/calibre/ebooks/conversion/plumber.py", line 1035, in run
File "site-packages/calibre/customize/conversion.py", line 241, in __call__
File "site-packages/calibre/ebooks/conversion/plugins/mobi_input.py", line 33, in convert
File "site-packages/calibre/ebooks/mobi/reader/mobi6.py", line 79, in __init__
struct.error: unpack requires a string argument of length 2

[kovidgoyal]

The file you are trying to convert is corrupted, it appears to be less than a 100bytes in size.

[Klaw]

OK Thank you!