Error transferring to Kobo, but not a database error!

[Joliet Jake]

I had a list of 12 ebooks. They are pretty low quality. I have Calibre 5.something and use Kobo Touch Extended.

I tried to transfer the set to my Kobo. I got an "error transferring to Kobo" error. I was able to transfer 7 books, one by one, but the other five gave me this error:

[Errno 2] No such file or directory: 'C:\\Users\\[name]\\AppData\\Local\\Temp\\calibre_qqqy877t\\6xmz1rwp _epub_container\\OEBPS\\Text\\0000_Discord.xhtml'

Traceback (most recent call last):
File "calibre\gui2\device.py", line 87, in run
File "calibre\gui2\device.py", line 628, in _upload_books
File "calibre_plugins.kobotouch_extended.device.driver" , line 426, in upload_books
File "calibre\devices\kobo\driver.py", line 2214, in upload_books
File "calibre_plugins.kobotouch_extended.device.driver" , line 209, in _modify_epub
File "calibre_plugins.kobotouch_extended.container" , line 119, in __init__
File "calibre_plugins.kobotouch_extended.container" , line 375, in __run_async_over_content
File "calibre_plugins.kobotouch_extended.container" , line 368, in __run_async
File "concurrent\futures\_base.py", line 432, in result
File "concurrent\futures\_base.py", line 388, in __get_result
File "concurrent\futures\thread.py", line 57, in run
File "calibre_plugins.kobotouch_extended.container" , line 291, in forced_cleanup
File "calibre\ebooks\oeb\polish\container.py", line 618, in raw_data
File "calibre\ebooks\oeb\polish\container.py", line 1075, in open
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\Users\\[name]\\AppData\\Local\\Temp\\calibre_qqqy877t\\6xmz1rwp _epub_container\\OEBPS\\Text\\0000_Discord.xhtml'

Not sure what was going on, I tried to transfer another ebook and it worked. I transferred a CBZ converted to an ePub and again it worked just fine. There was no database error.

Afterward I reconverted the five ePubs (with no changes) and it worked. All twelve ebooks came from the same source, all low-quality, and all look the same in Calibre.

I tried searching but I kept finding references to damaged databases. I think some of those posts were written by me!

[kovidgoyal]

That error indicates a broken EPUB file, as you discovered doing an EPUB to EPUB conversion before transferring will fix the file automatically.