How to fix metadata in iBooks using Calibre

Hi all, as with many others, the metadata of my books in iBooks was a huge mess. I couldn't find a solution online, so I tried and found a way to fix it, and figured I'd share the knowledge.

Used systems/ apps

- Mac OS High Sierra 10.13.6 with iBooks

- Calibre 3.37.0

• If you are using a different language for calibre you can change the language (temporarily) via calibre > preferences > interface > look & feel. Makes the below easier.
• Add your books to Calibre and fix all metadata as you want it. 

Note1: if you add custom columns (calibre > preferences > interface > add your own columns > add custom column) these don't seem to be added to the (exportable) metadata.

Note2: the transfer of column information is not great. The series column in calibre is not used in ibooks, so put series references in the titles, if you want that info available.

• Select all books and polish them.

"Polish books" can be added via calibre > preferences > interface > toolbars&menus > The main toolbar.

Check the "update metadata in the book files" and "remove a previously inserted book jacket".

• This creates original epub formats you want to remove.

Select all books > toolbar > small arrow next to Remove books > remove files of a specific format > select epub_original.

• Create a temporary folder (e.g. desktop/books). Select all books in the calibre app and drag (copy) to the temp folder.
• Remove all books from the calibre app.
• Remove all files from the calibre library folder in Finder. (You can move them to a different temp location if you are the careful type).
• Import the books stored in desktop/books into the calibre app (add books > add books from a single directory). This will recreate the library with proper metadata. Bonus: the library will be sorted according to your new metadata.

Note: when I tried this, it provided a 'read only' error. If that happens, just remove the calibre app and the calibre library folder, and reinstall calibre.

• Drag the books from calibre to ibooks.
• Clean up the temp folder(s).
• Done!

transference of the column information:

calibre > ibooks

title > title

author(s) > author

Tags > Category

Series > n/a

n/a > Collection