[Peter Blaise]

AttributeError: Custom field name '' must begin with '#'

... after successful editing cleanup and saving an EPUB, then trying to convert it to MOBI, which failed, so re-opening the EPUB in Calibre Ebook 7.10 editor gets the above error, and Caliber Ebook now refuses to open the EPUB for editing.

Calibre Ebook v7.10 apparently can't auto fix it?

Why present an error and not a fix?

I tried other in-computer and on-line converters and 'fixers', zipping and re-opening, all failed.

Anyway, how to fix it, please.

And how to PREVENT it.

Oddly, Calibre Ebook 7.10 itself can open the EPUB for reading on screen, no problem, end to end, the entire book is there exactly as it left the editing process.

Post Script - Amazon converted it to KFX just fine ( via email send EPUB to device ).

So, if Calibre Ebook can't 'fix' an "AttributeError: Custom field name '' must begin with '#'" by inserting a '#' itself, how can I do it outside the Calibre Ebook program to move forward after the Caliber Ebook program munged the EPUB?

Thanks.

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