I don't know much about Calibre, as I uninstalled it when I realized it wasn't actually writing metadata to the epub file but keeping it in its own database. That was after editing metadata in about 200 books I guess.
Looking at the FAQ on their website, it says:
Quote:
The list of books in calibre is blank!¶
In order to understand why that happened, you have to understand what a calibre library is. At the most basic level, a calibre library is just a folder. Whenever you add a book to calibre, that book’s files are copied into this folder (arranged into sub folders by author and title). Inside the calibre library folder, at the top level, you will see a file called metadata.db. This file is where calibre stores the metadata like title/author/rating/tags etc. for every book in your calibre library. The list of books that calibre displays is created by reading the contents of this metadata.db file.
There can be two reasons why calibre is showing a empty list of books:
Your calibre library folder changed its location. This can happen if it was on an external disk and the drive letter for that disk changed. Or if you accidentally moved the folder. In this case, calibre cannot find its library and so starts up with an empty library instead. To remedy this, do a right-click on the calibre icon in the calibre toolbar (it will say 0 books underneath it) and select Switch/create library. Click the little blue icon to select the new location of your calibre library and click OK.
Your metadata.db file was deleted/corrupted. In this case, you can ask calibre to rebuild the metadata.db from its backups. Click-and-hold the calibre icon in the calibre toolbar (it will say 0 books underneath it) and select Library maintenance->Restore database. calibre will automatically rebuild metadata.db.
|
http://manual.calibre-ebook.com/faq.html
There will be a contact address somewhere on that site I imagine.