Opening converted KePub fails with "Oops, this document could not be opened"

[Philipp Kapfer]

I've got several ePubs that, after being converted and uploaded to my eBook reader, don't open. The device shows an error dialog titled "Oops, this document could not be opened" with no further information other than contacting support. The original ePubs work perfectly both with the Adobe ePub viewer on the Kobo and renamed to *.kepub.epub. Attached are two examples of ePubs showing such behavior.

The eBook reader is a Kobo Aura HD with software version 2.8.1, I uploaded/converted the ePubs with calibre 1.6.0 and the Kobo Touch Extended plugin in version 2.2.9.

[Joel Goguen (jgoguen)]

There's HTML files in the source ePub books that have errors in them. Please try to fix the errors in the source ePub files and try the books again.

To fix the errors, you could open the books in Sigil and let it fix the errors, or you could try an ePub to ePub conversion in calibre. I think the easier option is to use Sigil, I tried this and it required no interaction aside from clicking "Yes" and fixed all of the problems.

[Joel Goguen (jgoguen)]

Forgot to note, processing "Witz und Weisheit der Scheibenw" locked up my computer for a few minutes. You could try an ePub to ePub conversion first in case there's something about the contents that's causing problems.

[Philipp Kapfer (crazyphilipp)]

I didn't have any problems with the conversion freezing calibre. Both books were converted within seconds. It's just Sigil that freezes for quite some time when opening Witz und Weisheit der Scheibenwelt.

I've opened and saved both ePubs in Sigil now. It did show a message that the ePub is invalid and repaired them. The repaired and converted files can now indeed be opened on the Kobo. The interesting thing, though, is, that Sigil 0.7.2 had no problems opening both ePubs and did not complain about any HTML errors even when checking with FlightCrew. Even in the new version 0.7.3 the only HTML errors are about "nbsp" entities, which, according to this thread (http://www.mobileread.com/forums/showthread.php?t=219360#9) is apparently a bug.

So I'm not really any wiser than before, other than the total restructuring Sigil performs on ePubs "magically" fixes the problem.

[Joel Goguen (jgoguen)]

Kobo has some specific expectations on the HTML contained in the KePub container. If the nbsp error is a bug in Sigil, it's perhaps possible that it may not have reported other errors. It's my (admittedly limited) experience that Sigil doesn't rewrite the document structure unless there's a problem with the structure.

[vladimir tasic (vladimir-tasicz)]

I also have this bug, and i sent you a epub and kepub via mobileread. New Aura HD FW 3.5.0, new vesion of the extension, epub without errors. Calibre didn't have any logs of the error.

[Joel Goguen (jgoguen)]

I refuse to accept copyrighted content delivered through a publicly accessible link. The directions I give are clear that books are to be uploaded to Launchpad bugs which are to be marked as Private. This is perhaps inconvenient, but it is to protect both you and myself from issues relating to distribution of copyrighted content; done my way, I can demonstrate that distribution is for the explicit purpose of fixing bugs in software and is intended to be non-public. The way you are trying to distribute books, you could be in trouble for illegal distribution of copyrighted content depending on the laws of your country. If you can't flag a bug as private for some reason (such as because you didn't create the bug) then create a new bug. Make sure to include everything I ask for.