Epub files suddenly not opening?

[KevinH]

I assumed he/she was copying epubs from calibre on a mac to calibre on a pc. I assume all are drm free. iBooks can be used to read non-drm epubs but does unpack them into an .epub folder. Still not sure what the issue is. Perhaps I am assuming wrong.

[ReaderofBooks]

Youre losing me guys, but no, I didnt have calibre on my Mac.
Not sure what to do next TBH.
I dont know how to fiddle with the permissions files.

[KevinH]

Did you try creating a second userid on your PC and test there,
or alternatively, did you try copying the epub to a usb key to another pc or mac to try there?

Were all of these epubs from iBooks on your mac? If not, what were you using to read them there?

[ReaderofBooks]

Hi,
I have a second user ID on the PC, and it doesnt seem to make any difference which one I use. One has full administrators privileges, and the other one doesnt.
I copied the epub book which is on my PC, and transferred it to a usb drive, and then stuck that usb drive into my macbook, and the epub book opened fine using ibooks on my mac.
[Yes, all of my books on the mac were only viewed using ibooks]
I dont know what that tells you, but hopefully it helps?
Thanks for trying to help.

[ReaderofBooks]

I should add, most of my epub books still seem to work fine, using calibre on the PC. Its only a few which are affected.
When the one example, I have posted, stopped working, I opened other books in calibre, and the layout of calibre had also changed.
There was no longer a grid showing the covers of my books, there were in a list, and when I opened the other epub books, which are still working, it was not one page, but three pages spread out with very small text, etc.
No-one has manually changed the layout. I dont know if thats relevant, or suggests something?
I only have the standard MS AV which came with win 10 pro.

[ReaderofBooks]

I tried converting it to mobi but that didnt work either.

Spoiler:

calibre, version 5.21.0 (win32, embedded-python: True)
Conversion error: Failed: Convert book 1 of 1 (The Memory Police)

Convert book 1 of 1 (The Memory Police)
Conversion options changed from defaults:
cover: 'C:\\Users\\Lenovo\\AppData\\Local\\Temp\\calibre_ asx7npl0\\xpbdcle4.jpeg'
read_metadata_from_opf: 'C:\\Users\\Lenovo\\AppData\\Local\\Temp\\calibre_ asx7npl0\\0w1hq6zp.opf'
output_profile: 'generic_eink'
verbose: 2
Resolved conversion options
calibre version: 5.21.0
{'asciiize': False,
'author_sort': None,
'authors': None,
'base_font_size': 0.0,
'book_producer': None,
'change_justification': 'original',
'chapter': "//*[((name()='h1' or name()='h2') and re:test(., "
"'\\s*((chapter|book|section|part)\\s+)|((prolog|p rologue|epilogue)(\\s+|$))', "
"'i')) or @class = 'chapter']",
'chapter_mark': 'pagebreak',
'comments': None,
'cover': 'C:\\Users\\Lenovo\\AppData\\Local\\Temp\\calibre_ asx7npl0\\xpbdcle4.jpeg',
'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': '',
'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 0x0000016A767BF5B0>,
'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_file_type': 'old',
'mobi_ignore_margins': False,
'mobi_keep_original_images': False,
'mobi_toc_at_start': False,
'no_chapters_in_toc': False,
'no_inline_navbars': False,
'no_inline_toc': False,
'output_profile': <calibre.customize.profiles.GenericEink object at 0x0000016A767BF8B0>,
'page_breaks_before': '/',
'personal_doc': '[PDOC]',
'prefer_author_sort': False,
'prefer_metadata_cover': False,
'pretty_print': False,
'pubdate': None,
'publisher': None,
'rating': None,
'read_metadata_from_opf': 'C:\\Users\\Lenovo\\AppData\\Local\\Temp\\calibre_ asx7npl0\\0w1hq6zp.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': '',
'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,
'transform_css_rules': '[]',
'unsmarten_punctuation': False,
'unwrap_lines': True,
'use_auto_toc': False,
'verbose': 2}
InputFormatPlugin: EPUB Input running
on C:\Users\Lenovo\AppData\Local\Temp\calibre_asx7npl 0\aou1w4po.epub
EPUB appears to be invalid ZIP file, trying a more forgiving ZIP parser
Traceback (most recent call last):
File "calibre\ebooks\conversion\plugins\epub_input. py", line 262, in convert
File "calibre\utils\zipfile.py", line 775, in __init__
File "calibre\utils\zipfile.py", line 810, in _GetContents
File "calibre\utils\zipfile.py", line 825, in _RealGetContents
calibre.utils.zipfile.BadZipfile: File is not a zip file

Traceback (most recent call last):
File "calibre\ebooks\conversion\plugins\epub_input. py", line 262, in convert
File "calibre\utils\zipfile.py", line 775, in __init__
File "calibre\utils\zipfile.py", line 810, in _GetContents
File "calibre\utils\zipfile.py", line 825, in _RealGetContents
calibre.utils.zipfile.BadZipfile: File is not a zip file

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "runpy.py", line 194, in _run_module_as_main
File "runpy.py", line 87, in _run_code
File "site.py", line 82, in <module>
File "site.py", line 77, in main
File "site.py", line 49, in run_entry_point
File "calibre\utils\ipc\worker.py", line 216, in main
File "calibre\gui2\convert\gui_conversion.py", line 41, in gui_convert_override
File "calibre\gui2\convert\gui_conversion.py", line 28, in gui_convert
File "calibre\ebooks\conversion\plumber.py", line 1105, in run
File "calibre\customize\conversion.py", line 245, in __call__
File "calibre\ebooks\conversion\plugins\epub_input. py", line 269, in convert
File "calibre\utils\localunzip.py", line 253, in extractall
File "calibre\utils\localunzip.py", line 240, in _extractall
ValueError: Not a ZIP file

[davidfor]

Originally Posted by ReaderofBooks

I tried converting it to mobi but that didnt work either.

That is to be expected. Preparing a book to view and convert shares a lot of code.

The error, as others have said, is that the file is not a valid zip file. A simple test is to open it with an zip file viewer. That might give a better error about why it doesn't open.

The fact that it opens in iBooks on a MAC suggests that @KevinH is probably on the right track about the format. If that was the original source, it probably means it is has whatever DRM iBooks uses.

[BetterRed]

Originally Posted by ReaderofBooks

…
There was no longer a grid showing the covers of my books, there were in a list…

You probably hit Alt+Shift+G - see Keyboard shortcuts

Originally Posted by ReaderofBooks

…and when I opened the other epub books, which are still working, it was not one page, but three pages spread out with very small text, etc.

That suggests you changed some setting or hit a another shortcut e.g. Ctrl+-. And/Or you changed the Viewer's Page Layout preference settings, see ==>> Customizing the look and feel of your reading experience

BR

[ReaderofBooks]

I have already changed the file extension to zip as was suggested, as per post number 12.
I do not think I accidentally randomly hit shift alt and g together.
Ill have to go back to ibooks I think.
Thanks.

[JSWolf]

Can you go to the sources of these eBooks and download them again using your Lenovo?

[KevinH]

If they are iBooks epubs, and you bought them through iBooks or iTunes, they can only be read by iBooks due to DRM.

If you bought them someplace else and stripped the DRM or they were DRM free, and only read them in iBooks, iBooks may have unzipped those epubs into a folder and renamed that folder with a .epub extension. If so, you may be able to use an epub zip tool on your mac to re-zip them up back into an actual epub file before copying them to your PC where they should work just fine in calibre.

[theducks]

Originally Posted by ReaderofBooks

I have already changed the file extension to zip as was suggested, as per post number 12.
I do not think I accidentally randomly hit shift alt and g together.
Ill have to go back to ibooks I think.
Thanks.

JUST Changing the extension does not make it a Zip.
Zipping is a process that includes compression.