[belle39234]

I purchased a used libra 2 and I'm in the process of migrating my library to it. My library is in epub and kfx formats because I already have a kindle basic. converting all my books to kfx worked well, but not all of them convert well to kepub.

I've tried 2 methods of conversion from epub:

calibre inbuilt conversion from epub to kepub, which didn't convert my ebooks well(puts spaces between paragraphs, if I tried the 'remove space between paragraphs', it also removed spaces that should not be removed and ruined some centre aligned text) so I ditched that.

the 'use kobo viewer for epub' setting from koboutilities plugin which works much better, preserved formatting very well, but results in some ebooks not opening at all. I get a 'oops, this document couldn't be opened, there might be a problem with the file' error message on kobo. upon investigation, all these epubs were purchased from the same publisher(DRM free as well so I never had to make any changes bar for editing metadata), and if I use the 'check book' (F7) option, they all display an error like this:

The id _idContainer001 is not a valid id. IDs must start with a letter ([A-Za-z]) and may be followed by any number of letters, digits ([0-9]), hyphens ("-"), underscores ("_"), colons (":"), and periods ("."). This is to ensure maximum compatibility with a wide range of devices.

once I fix that and resend them, they work! the issue is, I have 300 books from that publisher and some of them do work right off the bat so is there a way to find them? there's an odd book or few from other publishers that has the same issue, how do I hunt them all down without checking every book in my library? I've tried quality check which didn't catch it, I've tried converting them and the id remained unchanged. any ideas welcome!