Hi Theducks.
Think I should have stated this first, but I didn't make
no one change to the files between the actions through Calibre (basically one export by 'Save', one import by 'Add'.
I understood that .opf shouln't be mandatory as metadata are already included in the epub itself, but this is the error message I get : see attached.
This is frustrating because as I wrote, I didn't make anything manually; the epub file has been saved with calibre, and added to a new calibre library.
Any idea about the error message ?
